Preheat oven to 350 degrees.
Brown ground beef and onion over medium-high heat until beef is cooked through; drain.
Return the beef and onions to the skillet and add taco seasoning.
Stir in the enchilada sauce. Leave on low heat to simmer for 10 minutes.
Spray a 9 x 9 baking dish with cooking spray.
Lay the first tortilla in the dish and sprinkle meat mixture on top, taking it all the way to the edges.
Then sprinkle a layer of cheese on top.
Cover with another tortilla and repeat until you use all four tortillas.
Sprinkle top layer with more cheese and bake at 350 degrees for 15 minutes until heated through.
Serve with your choice of topping such as sour cream, salsa or guacamole.
