Question is pretty straightforward in the title
Let's begin with an definition of "good". G-d gave us the free will to chose for ourselves. The best thing to do is to chose G-d and His Torah, since Torah is called good. So "good people", according to this principle, are people that follow G-d ways, cling to Him and His Torah, and observe mitzvos.
A Jewish perspective can be found in the commentary of the Ramchal. In Derech Hashem, he writes:
As we have discussed, humanity is the creature created for the purpose of drawing close to G-d. They are placed between perfection and deficiency, and it is in their hands to earn perfection. Humanity must earn this perfection, however, through their own desire and choice because if they were forced to choose perfection then they would not actually be its master, and G-d's purpose would not be fulfilled. It as therefore necessary to create humanity with free will. One's inclinations are therefore balanced between good and evil and they are not compelled toward either. They have the power of choice, able to choose either side knowingly and willingly, as well as to possess whichever one they wish. Humanity was therefore created with both a good urge and an evil urge. They have the power to incline in whichever direction they choose.
According to this view by the Ramchal, G-d provided us with both inclinations; we are the one to chose what to go after, our good or evil instincs (G-d forbid). If man was natural bad or good, that would do-away our free will, right?
Since this is a Judaism-stackexchange, I would not add it into this answer, but I would recommend delving into the philosophical, theoratical debate between Thomas Hobbes and Jean-Jacques Rousseau, it is a (secular) theory that describe man as either: natural good (according to Rousseau) and not natural good (according to Hobbs).
Similary, the Hasagot HaRaavad writes:
and this very same is the power endowed to man to be either good or bad
Rambam writes similair:
Free will is granted to all men. If one desires to turn himself to the path of good and be righteous, the choice is his. Should he desire to turn to the path of evil and be wicked, the choice is his.
See also Avos 1:7:
Nittai the Arbelite used to say: keep a distance from an evil neighbor, do not become attached to the wicked, and do not abandon faith in [divine] retribution.
The Rambam, in Hilchos De'os writes:
Each and every human being has many dispositions, and each one is both very different and very distant from any other: One person may have a violent temper, always angry; but another's mind is at ease and he is never angry, or if he does feel anger it is a soft anger once in several years.
So yes, as you wrote in one of the comments, a person might lean towards a specific character trait. That does not mean that he is unable to grow out of that trait, in order to be a better person. See also the commentary of the Divrei Yirmiyahu on the Rambam.
So yes, a person has both good and bad inclinations, that is the way Hashem made us. We have good-will, we are meant to take care of ourselves and to attach ourselves to G-d, but we are free to do that, or not (G-d forbid). G-d does not force us into doing that.
How does one train oneself to obtain a good character for instance? The Rambam teaches:
By constant, repetitive practice of the actions [characteristic of] moderate dispositions and drilling over and over, constantly, until these actions are easy and are no longer a burden upon him. And [these] dispositions will [then] become fixed in his personality.
I would recommend reading Tanya by the Alter Rebbe, regarding the subject of a "beinoni". The Gemara defines that as:
With regard to one’s inclinations, it was taught in a baraita that Rabbi Yosei HaGelili says: The good inclination rules the righteous, as it is stated: “And my heart is dead within me” (Psalms 109:22); the evil inclination has been completely banished from his heart. The evil inclination rules the wicked, as it is stated: “Transgression speaks to the wicked, there is no fear of God before his eyes” (Psalms 36:2). Middling people are ruled by both the good and evil inclinations, as it is stated: “Because He stands at the right hand of the needy, to save him from them that rule his soul” (Psalms 109:31).
I'm familiar with three different approaches,
Raschar Hirsch (Bereshith 2) says that the human nature is neither good nor bad in itself, but rather blind - a structure of various forces and drives, that, by doing "their thing", might lead to positive results, but may as well lead also to sin. So whilst passion, emotion, intellect, aren't to be "fought" against, since they are not intristically evil, they are rather not trustworthy, and only HaShem's commandment can direct them to the virtue; also being "nice" by default, that is, without the active intention to obey HaShem's will, isn't considered particularly virtuous, because by sticking to a predisposed nature a man serves merely himself.
Rav Avraham Kook (Orot Hatora 11) talks about how a Jew should "believe in his life", believe in his feelings and senses that they lead him in a righteous path by nature, only that the Torah is there to help him to avoid some mistakes or delusions.
The Tanya (based on מהרח"ו so in that it's pretty much concensus amongst the Kabbalic schools) makes a distinction between the animalistic part and the divine part of the personality - the animalistic part is basically the entire personality, passions, emotions, intellect, drives, except the will to do HaShem's will which is the only thing that's divine,
And also talks about the idea that everything that is not divine is naturally bad by definition by not being actively and conciously inline with HaShem's will.
So that a person is both good and bad, bad by "default", good by divine consicence.
Thus we have three completely different styles:
Acc. to Tanya by actively fighting the animalistic nature a person could gain virtue (Tanya 27, 29), with the "default" personality (of the Benoni that is) as something that our sole purpose is to overcome, being insignificant, since not divine.
Acc. to Rav Kook, on the contrary, we should strive to develop our intristically good intentions, whilst being aware of possible mistakes.
Acc. to Rav Hirsch, we should approach our personality "skeptically", we should carefully try to "fit" it in the Torah, not destroy, not "consecrate".
As pointed out, this is hard to answer without definitions.
I wanted to highlight two points that had not been made yet:
After Hashem created everything, culminating in the creation of Adam, the Torah says that the creation was "very good" (טוב מאד). The Ramban writes that some say that the "very good" actually refers to the evil inclination of man. He also cites Onkelos who translates very good as "very orderly" meaning that the order was very properly arranged since the evil is needed for the preservation of the good. He also cites Bereishit Rabba saying that on account of the superiority of man the Torah adds the phrase "very good".
From this we may conclude that we inherently have both good and evil within us, at least an inclination to both.
Another relevant source that wasn't mentioned in other responses is Bereshit 8:21 following when Cain killed Hevel:
וַיָּ֣רַח יְהֹוָה֮ אֶת־רֵ֣יחַ הַנִּיחֹ֒חַ֒ וַיֹּ֨אמֶר יְהֹוָ֜ה אֶל־לִבּ֗וֹ לֹֽא־אֹ֠סִ֠ף לְקַלֵּ֨ל ע֤וֹד אֶת־הָֽאֲדָמָה֙ בַּעֲב֣וּר הָֽאָדָ֔ם כִּ֠י יֵ֣צֶר לֵ֧ב הָאָדָ֛ם רַ֖ע מִנְּעֻרָ֑יו וְלֹֽא־אֹסִ֥ף ע֛וֹד לְהַכּ֥וֹת אֶת־כׇּל־חַ֖י כַּֽאֲשֶׁ֥ר עָשִֽׂיתִי׃
יהוה smelled the pleasing odor, and יהוה resolved: “Never again will I doom the earth because of humankind, since the devisings of the human mind are evil from youth; nor will I ever again destroy every living being, as I have done.
This implies that a person may be evil from the outset. However, Rashi merely says that from birth a person is given an evil inclination, possibly implying that the good inclination is already within him/her.
There are many angles to this, but since it is the zman, here's a chassidic idea that is noge'ah to Purim. There is a theological concept that Hashem is beyond any form of definition (see for example Gevurot Hashem Hakdama 2 - Maharal).
This means even beyond good and evil, which Hashem created.
Hashem therefore perfectly Self Defines with true bechirat chofshit, free will, which is what a real Might One does, so to speak.1
He invites us to do the same. Just one problem, we are made in His image, and He defines Himself as good and everything He does is good and we are something He did!
So Hashem creates a situation whereby we are able to also go beyond definition (l'havdil). We have this uncanny ability to define ourselves any way we want - as well as a strong desire to do so, and a strong resistance to being externally defined.
So, are we inherently good? In truth, yes. In fact, no. The whole point is to earn our good, and that's where this mission of self definition comes in - we are meant to define ourselves as good. This is where we bring up discussion about the Yeitzer Hara and Yeitzer Hatov, the tzimtzum, the chet, and so on; the mechanics of how He achieved this, and the particulars.
Where does Purim fit in? Purim takes us to the highest. Defining ourselves as good isn't enough. This makes us into perfect Tahorim, but not Chassidim (see Mesilat Yisharim ch.16&18 respectively).
The highest is defining ourselves as His. This is something that He Himself can relate to, as this is what He created the world for (see Derech Hashem, 1:2 - to give Himself to another2).
Him defining Himself as ours, and us defining ourselves as His, goes beyond reason. This comes from the concept of "ad delo yada", 'until you don't know'. Don't know what? The difference between Baruch Mordechai, Arur Haman, meaning even if, chas veshalom, it had been the other way around and Haman was the blessed one and Mordechai was the cursed one, Hashem would still choose and want Mordechai. This is something we would get deeper if we were to understand the gravity of going against His will, and yet having done so terribly for so long, He is still ours... Or having a great Purim.
When we are in this kind of relationship of beyond-reason Oneness2, you are beyond good and evil.
So in essence, are we good or evil? No. We are Jews. We are His. There's nothing more "good" than that.
Here is a shiur that goes in depth with many of the aforementioned ideas if anyone wishes to go deeper. A great pre-Purim warm up!
1 - Trying not to condense too much here, but I think it makes basic sense that if Hashem, omniscient, is not under the power of anything outside Himself in any way at all, He is "free" of influence and therefore all His choices are 100% His, i.e. truly "free" will.
2 - Ramchal explains that the purpose of creation is for Him to give the perfect good to another, and then defines that perfect good as nothing but Him. See also Tanya which goes into more about this.
3 - sometimes referred to as the "50th gate of wisdom", which goes beyond wisdom, if you've ever seen that phrase. This is discussed in many Chassidic discourses - discussion of Hashem's Ratzon and the Baal HaRatzon will be relevant if one gets a chance to study this.