The term Mexican is a mixed bag because Mexico's diversity almost rivals our own.
A Mexican could be a member of an indigenous Native American tribe, they could be part of "los indios" (República de Indios) which was held separate from the "Republic of Spaniards" (República de Españoles), they could carry German DNA, thanks to the massive German influx of the 19th century, they might carry Moorish blood, there may be Aztec or a mix of Mestizo heritage. The Pima and Concho, Rio Grande, Pueblo, Apache and Yumas tribes crossed back and forth numerous times over the then nonexistent US borders, even the Chumash were known to venture into Mexico for trade.
With well over eighty indigenous languages, the Mexican racial and cultural totem pole is tall indeed.
But in any case, Elizabeth Warren made mention of it as a reference to family stories handed down through generations, not as any attempt to position herself IN the Native American tribal community, or to receive compensation in the form of so called "Indian checks" or to position herself in any advisory capacity on a casino board or other tribal asset revenue scheme.
She didn't even name a specific tribe. Donald did.
Calling her "Pocahantas" means Trump assumed she had Powhatan blood.
That's all on him and his Republican butt kissers.