Combine salsa, taco seasoning, and a few large pinches of salt and pepper in a crockpot insert.
Nestle chicken breast into the salsa mixture.
Cover and cook on high for 2 hours or on low for 4 hours.
Shred chicken with two forks.
Serve inside flour tortillas with diced red onion, fresh chopped cilantro, and a sprinkle of Cotija cheese and enjoy!
