On the pasuk of "הָ֤בָה נָּא֙ אָב֣וֹא אֵלַ֔יִךְ" there is a dagesh in front of a word on a the letter nun. What type of Dagesh is this? Shouldn't there not be a dagesh chazak on front of a word?
I believe the answer is that this type of dagesh is a Deḥiq (דחיק 'compressed') The reason for the dagesh in נא is because of a phenomenon known as deḥiq (aka, apparently, ate meraḥiq). Deḥiq is the name for when a word receives an initial dagesh when:
1) The word before the word getting the deḥiq end in a vowel.
2) The stress on the word preceding that with the deḥiq is penultimate (milʿel)
3) The stress on the word preceding that with the deḥiq is marked by a conjunctive accent (or a maqef merges the words).
4) The stress on the word receiving the deḥiq is on the initial syllable (or one after a shewa naʿ). More rarely, the stress on the word getting the deḥiq is not initial, but an initial secondary stress is present (marked by a gaʿya), e.g. וְעָשִׂ֤יתָ סִּֽירֹתָיו֙ (Shemot 27:3).
See below for more information.