Begin by slicing the red, green, and yellow bell peppers, as well as the onion, into thin strips.

In a medium bowl, combine boneless, skinless chicken breasts with olive oil, cumin, chili powder, garlic powder, salt, and pepper. Toss until well-coated.

Layer the sliced bell peppers and onions at the bottom of the crockpot.

Carefully place the seasoned chicken on top of the vegetables and drizzle with lime juice.

Cover the crockpot and set it to cook on low for 6 hours or high for 3 hours.

Once cooked, shred the chicken using two forks and mix it with the vegetables.

Serve in warm tortillas or lettuce wraps and top with optional ingredients.