Which Native American tribe was an enemy of the Wichita and an ally of the Spanish in Texas?

The Querechos or Apaches.

The Wichitas fought wars with other tribes. They didn't fight over territory, but instead to prove their courage. Some tribes the Wichitas frequently fought and consider their enemies were the Apaches.

During the end of the Spanish rule, the Apaches staged constant attacks against the Spanish missions. But as de 1700s wore on, they found themselves subject to attacking from the fearsome Comanches. Eventually, they entered an on-again, off-again relationship with the Spanish, sometimes warring and attacking, other times allying with the Spanish against the Comanches and other enemies. Those peace efforts with the Spanish resulted in the establishment of Spanish missions.