Place the chicken in the bottom of the slow cooker.
Top with black beans, tomatoes, corn, salsa, onion, green pepper, and cilantro.
Whisk together lime juice, olive oil, cumin, chili powder, and garlic powder.
Pour over chicken and vegetables.
Cook on high for 3-4 hour or low for 6-7.
Serve over rice, topped with cheese, sour cream, and sliced avocado, if desired.