What evidence most clearly indicates that the aztec people migrated to mexico from the american southwest?

An active turquoise trade existed between the regions.

Tortoise gemstones was extremely valuable for the Aztec and the ancient Pueblo people. It was used to make  exquisite ritual masks with turquoise mosaic on wood, shell, and bone.  They also made turquoise jewelry, pottery and fabrics, and trading these with neighboring and distant communities for a wide variety of goods including exotic items such as seashells, copper bells, parrots and macaws. the pueblo are an ancient people related with the Aztecs.