Heat oven to 425°F. Spray an 8x8 or 9x9 baking dish with nonstick cooking spray or rub it with some cooking oil.
Slice tortillas into thick strips (about 4 to 5 strips per tortilla).
In a large mixing bowl, combine corn, green chiles, black beans, and chicken.
In the prepared baking dish, start layering ingredients by first spreading a thin layer of enchilada sauce on the bottom.
Top with tortillas, vegetable / chicken filling, enchilada sauce, and cheese.
Repeat until all of the ingredients have been used, finishing the top with tortilla strips, vegetables / chicken, and enchilada sauce (reserve 1/2 cup of cheese to finish the dish after baking).
At this point, casserole can be refrigerated for up to 3 hours or frozen for up to 6 months.
To bake, cover the enchilada casserole tightly with aluminum foil. Place it on a sheet pan (in case it bubbles over).
Bake, covered, for 20 minutes (add 10 to 15 minutes if the dish has been refrigerated before baking).
Remove foil and add the remaining 1/2 cup of shredded cheese.
Return casserole to oven and continue baking, uncovered, until cheese is melted, about 10 minutes more.
Let casserole rest for 10 min before slicing. (The slices will hold together better if it’s slightly cooled before serving.)
Serve immediately with any toppings you’d like!