In that comment on that verse (Genesis 46:1), the Ramban writes:
וחס ושלום שיהיה הדבר הנקרא שכינה או כבוד נברא חוץ מהשם הנכבד יתברך
and heaven forbid that that which is called "Shechinah" or "Kavod Nivra" (Created Glory) is something other than Hashem the Glorious, may He be blessed.
He is discussing there Unqelus's norm of unpacking anthropomorphic descriptions of Hashem. In particular, his use of "Kavod Nivra".
The same conversation comes up in the Ramban's treatment of Rav Saadia Gaon and the Rambam's treatment of the "Man in the Throne" seen by the Seventy Elders at Mount Sinai.
Rav Saadia Gaon (Emunos veDei'os 2:10) says they saw the Kavod Nivra. The vision at Mount Sinai and that of Yechezkel were not of Hashem, as that is logically impossible. Rather, they saw this kavod. The Rambam’s approach is similar to Rav Saadia’s, except that he writes (Moreh Nevuchim 1:64) that the phrase “Kevod Hashem” is a synonym; it could refer to either Hashem Himself, in all His glory, or it could be used to refer to the kavod nivra. In our case, the text means that they saw the kavod nivra. However, in Moshe’s later request, he was asking to see Hashem Himself, which is why he was unable to have his desire granted.
Rav Sa’adia Gaon writes that the shechinah is indeed part of the physical world, but that it is a kavod nivra. In fact, Rav Sa’adia Gaon holds that the term “shechinah” refers to any miraculous thing that reminds the viewer that Hashem is shochein beqirbo, dwelling with him. Thus, the pillars of fire and of cloud were the shechinah, as were the vision of Mount Sinai and of the Merkavah. Rav Sa’adia Gaon’s notion of kavod nivra can be a physical object. Therefore this vision could occur through regular, physical sight.
This is where the Rambam’s opinion diverges. He holds (Moreh Nevuchim 2:6) that the kavod nivrah could only be seen prophetically. It is different in kind to the pillars of fire and of smoke, which were physical entities created miraculously.
The Ramban disagrees with both. In our verse, the Ramban says that “Sh-echinah” is a name of Hashem, not a created thing (nor a class of them). However, this does not mean that Mosheh and the elders actually saw Hashem in human form. The Ramban on our verse explains that the vision was prophetic. To the Ramban, nevu'ah is a message, and the things "seen" in it are symbols in that message, not (as the Rambam would have it) the experience of metaphysical existences. This is what frees him up to saying that the Sh-echinah can really be G-d Himself even though it is seen in prophecy.