Preheat oven to 350°F; spray a 9x13-inch dish with cooking spray.
Mix chicken, 1 cup enchilada sauce, chiles, sour cream, 1 cup cheese, cumin, garlic powder, salt, and pepper in a large bowl.
Spread ½ cup enchilada sauce in dish.
Layer half the tortillas over sauce, then half the chicken mixture and ⅔ cup cheese.
Repeat with remaining tortillas, remaining chicken mixture, and ⅔ cup cheese.
Pour remaining enchilada sauce over top; finish with remaining cheese.
Cover with foil; bake 25 minutes. Uncover; bake another 10 minutes until cheese bubbles and turns golden.
Rest 5 minutes; serve with favorite garnishes such as cilantro, tomatoes, or avocado.