Season the chicken: Place the chicken in the crockpot and sprinkle with the chili powder, cumin, smoked paprika, garlic powder, onion powder, and salt.
Add the liquid: Pour in the broth and lime juice.
Cook: Cover and cook on low for 5 hours or high for 2.5 hours, until the chicken reaches 165°F.
Add the vegetables: Shred or slice the chicken, then stir in the bell peppers and onion. Cover and cook on high for another 45-60 minutes, until the vegetables are tender-crisp.
Serve: Pile into warm tortillas with your favorite toppings.
Notes
Add the peppers and onion in the final 45-60 minutes on high, not at the start, or they turn to mush over the full cook.