Preheat oven to 350°F.
In a large bowl, mix chicken, 1 cup Monterey Jack cheese, green chiles, sour cream, garlic powder, onion powder, cumin, salt, and pepper.
Warm tortillas in the microwave for 20 to 25 seconds.
Spread ½ cup enchilada sauce in the bottom of a 9×13 dish.
Add 6 tortillas, slightly overlapping.
Spread half of the chicken mixture over tortillas.
Pour half of the remaining sauce on top.
Add 6 more tortillas.
Spread the rest of the chicken mixture.
Add the final tortillas and top with remaining sauce.
Sprinkle the remaining Monterey Jack and cheddar cheese over the casserole.
Bake for 30 to 35 minutes, until bubbly and melted.
Let rest 10 minutes before slicing.
Garnish with cilantro or diced onion if desired.