Place sliced onion and bell peppers in the bottom of a crockpot and coat with oil.

Place chicken breasts on top of the peppers and onion, and drizzle with oil.

Sprinkle with chili powder, cumin, garlic powder, salt, and pepper.

Rub the seasoning into each chicken breast.

Cover and cook on low 4-6 hours.

Once cooked, shred the chicken and return it to the crockpot.

Serve the chicken and veggies on tortillas and enjoy!