In a small bowl, combine chili powder, paprika, onion powder, sea salt, garlic powder, ground cumin, oregano, black pepper, cayenne pepper and red pepper flakes.
Lay chicken breasts on the bottom of crock pot.
Sprinkle seasoning mix evenly over all sides of the chicken.
Cover chicken with salsa.
Cook on low for 4-5 hours, or high for 2-3 hours, or until chicken breasts are tender.
Use two forks to shred the chicken directly in your crock pot.
Serve in taco shells with topping of your choice.