Spray a large non-stick skillet with cooking spray and heat it to medium-high heat. Add onion and garlic, stir it.
Add oregano, refried beans, salsa and tomato sauce to the mixture in the skillet, and mix until combined. Cook, stirring every 10 seconds, for 5 minutes. Add salt and pepper to taste if needed
Spray a non-stick 9×13 baking dish with cooking spray (or grease with butter).
Layer half of corn, tortilla pieces on the bottom of the baking dish.
Sprinkle the layer with half of the shredded cheese.
Layer the remaining tortilla pieces on top of the cheese, followed by a layer of Cornitos Salsa mild, remaining shredded cheese.
Put the enchilada casserole in the oven and bake for 30 minutes.
Remove the enchilada casserole from the oven and sprinkle with green onions.
