What Montezuma's Aztec Sounded Like – And How We Know

i showed this to a mexican friend of mine (who only knows [mexican] spanish and english), and she told me that the pronunciation in the video sounds off---a bit too "english".

she doesn't know any of the the languages described in the videos, but she says one becomes familiar with quite a lot of native words when learning mexican spanish, because it borrows a lot of native words. i believe her; her name after all, is of native origin...and that for some reason is worth a little more to me than a youtuber's pronunciation---what fallacy am i falling into there?