In a large mixing bowl, combine the chicken breasts, enchilada sauce, corn, black beans, cumin, garlic powder, onion powder, chili powder, and salsa. Mix well to ensure the chicken is coated in the sauce and spices.
Layer four corn tortillas in the bottom of the crockpot, breaking them apart as needed to cover the base.
Spread half of the chicken mixture over the tortillas and sprinkle with 1 cup of shredded cheddar cheese.
Add another layer of tortillas, followed by the remaining chicken mixture, and top with the last layer of tortillas.
Sprinkle the remaining 1 cup of cheddar cheese on top.
Cover the crockpot and cook on low for 6 hours or until the chicken is fully cooked and easy to shred.
Once cooked, carefully remove the chicken and shred it using two forks. Return the shredded chicken back to the crockpot and stir to combine with the other ingredients.
Let it sit for about 10 minutes before serving to allow the flavors to meld.
Serve warm, garnished with fresh cilantro and sliced avocado if desired.