Step 1: Prepare the Ingredients: Slice bell peppers and onions into thin strips. Mince garlic and set aside.
Step 2: Assemble in Crockpot: Place chicken breasts or thighs in the bottom of the crockpot. Top with sliced peppers, onions, and garlic. In a small bowl, combine chili powder, cumin, smoked paprika, oregano, salt, black pepper, and crushed red pepper flakes. Drizzle olive oil and chicken broth over the chicken and veggies. Sprinkle the spice mixture evenly on top.
Step 3: Slow Cook: Cover and cook on low for 4-6 hours or high for 2-3 hours, until chicken is cooked through and tender. About 10 minutes before serving, drizzle lime juice over the top.
Step 4: Shred the Chicken: Remove chicken from the crockpot and shred using two forks. Return shredded chicken to the crockpot and stir to combine with peppers, onions, and juices.