01 - Lightly grease the inside of a 6-quart crockpot with cooking spray or oil.
02 - Place the chicken breasts in the bottom of the slow cooker. Sprinkle evenly with cumin, chili powder, garlic powder, salt, and pepper on both sides.
03 - Layer the diced onion, red bell pepper, frozen corn, and drained black beans over the seasoned chicken.
04 - Pour 1 cup of enchilada sauce evenly over the vegetable and bean mixture.
05 - Arrange half of the quartered tortilla pieces over the sauce mixture. Top with 1 cup of the shredded Mexican cheese blend.
06 - Pour the remaining 1 cup of enchilada sauce over the cheese layer. Add the remaining tortilla pieces and top with the final cup of shredded cheese.
07 - Cover and cook on low heat for 4 hours, or until the chicken is cooked through and tender (internal temperature reaches 165°F).
08 - About 20 minutes before serving, remove the lid and shred the chicken directly in the crockpot using two forks. Mix thoroughly to combine all ingredients. Cover and let sit for 15-20 minutes to allow flavors to meld.
09 - Serve hot, garnished with chopped fresh cilantro, sliced green onions, and a dollop of sour cream if desired.