Preheat the oven to 425 degrees F (220 degrees C)
Stir chicken, green enchilada sauce, and 1 cup cheese together in a bowl
Reserve 2 tablespoons green onions for topping
Add remaining green onions to chicken mixture and set aside
Drizzle oil in the bottom of a deep 9x13-inch baking dish
Add half the chips to the dish and top evenly with beans and 1 cup cheese
Pour ¾ cup red enchilada sauce over the top
Spread chicken mixture evenly over the sauce and top with remaining chips
Pour remaining red enchilada sauce evenly over the casserole and top with remaining cheese
Cover with foil
Bake in the preheated oven for 20 minutes
Uncover and cook until browned and bubbly, about 10 minutes longer
Serve topped with desired toppings
