In a large mixing bowl, combine the shredded chicken, black beans, corn, enchilada sauce, diced tomatoes, cumin, chili powder, garlic powder, salt, and pepper. Mix well until all ingredients are evenly combined.
Layer the bottom of the crockpot with two small flour tortillas, tearing them as needed to fit.
Spread half of the chicken mixture over the tortillas in the crockpot.
Sprinkle 1 cup of shredded cheese over the chicken mixture.
Repeat the layers with two more tortillas, the remaining chicken mixture, and another 1 cup of cheese.
Top with the last two tortillas, and then add the remaining cheese on top.
Cover the crockpot and cook on low for 6 hours, or until the cheese is melted and bubbly, and the casserole is heated through.
After cooking, allow the casserole to cool for a few minutes before serving.
Serve with optional toppings like chopped cilantro, sour cream, sliced jalapeños, or avocado.