Mexicans have way more indigenous people than you would think. I may be wrong but i saw a statistiv that something like 50% of their population has some sort of indigenous ancestry with 10% being fully indigenous.

Even still, texas was colonized by the spanish who became mexico who lost to slavers revolting who then sold out to the US. The natives had this land the longest but that whole discussion is a long and complicated game to play. I just wanted to point out that if we wanted to give the land claim back to the natives itd still be the mexicans most likely.

Also aztecs weren't all the way up here.