:’) IMHO, the most probable idea is, the two places look alike, and the migration of Nahautl speakers (Navaho is in the family, if memory serves) wound up in a lot of places. According to the legend, the ancestors of the Aztecs had to flee the island due to some problem (a disaster), and the generations of wandering were in a darkened world, (again, if memory serves), making the leap between Aztlan and Atlantis almost plausible — but due to the wide disparity of millennia between the two, not remotely plausible.
At least two earlier big-shot civs in Mexico — Teotihuacan, and the Toltecs (probable capital was Tula, ancient Tollan) came and went in that order; in Bernal Diaz, there’s a description of a battle fought by the Spaniards as they fled the Aztec capital the first time. It was fought in one of these two sites I think, and by that time the Aztecs had no tradition of the origin of the buildings, attributing it to gods. It was one of those amazing escape moments, worth reading about. :’)
Anyway, the upshot is, earlier civs were completely not in their traditions, which IMV does a few things, A) mitigates against the reliability of a so-called oral tradition, and B) mitigates in favor of an oral tradition in the case of the Aztec origin myth. See, I make my own fun...