01 - Lightly grease the interior of a 6-quart crockpot with cooking spray or a small amount of oil.
02 - Arrange chicken breasts in the bottom of the slow cooker. Rub evenly with cumin, chili powder, garlic powder, salt, and black pepper.
03 - Spread diced onion, red bell pepper, frozen corn, and drained black beans evenly over the seasoned chicken.
04 - Pour 1 cup of enchilada sauce over the vegetable and bean mixture.
05 - Arrange half of the quartered tortilla pieces over the sauce mixture. Sprinkle with 1 cup of shredded cheese.
06 - Repeat layers with remaining enchilada sauce, tortilla pieces, and remaining cheese.
07 - Cover and cook on low setting for 4 hours, until chicken is fully cooked through and tender.
08 - Twenty minutes before serving, shred chicken directly in the crockpot using two forks. Stir thoroughly to incorporate all ingredients and recover.
09 - Serve hot, topped with fresh cilantro, sliced green onions, and a dollop of sour cream if desired.