Preheat the oven to 400°F (200°C) and spray a 9 x 13-inch casserole dish with nonstick spray.
In a large bowl, combine the shredded chicken, sour cream, half of the shredded cheddar, 1 teaspoon of the cumin, 1/2 tablespoon of the chili powder, the kosher salt, and half of the black pepper; mix until evenly coated.
In a second bowl, stir together the corn, black beans, the remaining 1 teaspoon cumin, remaining 1/2 tablespoon chili powder, and the remaining black pepper until combined.
Place two tortillas side by side in the bottom of the prepared casserole dish to form a layer.
Spread half of the chicken mixture evenly over the tortillas, then spread half of the bean-and-corn mixture over the chicken.
Top with the remaining two tortillas, then repeat with the remaining chicken mixture and remaining bean mixture.
Sprinkle the remaining shredded cheddar over the top layer.
Bake uncovered for 20 minutes, or until the cheese is melted and the casserole is heated through.
Let the casserole rest for a few minutes before cutting and serving hot.
