Preheat the oven to 375°F.
Add the ground beef and onion to a heavy skillet that's been sprayed with no stick spray (or a tablespoon of oil).
Cook over medium heat, stirring often and breaking up chunks of ground beef.
When the meat is fully cooked and the onions have softened add the taco seasoning, beans, and enough of the water to moisten the mixture.. Stir.
Spread ¼ cup of the enchilada sauce evenly over the bottom of the baking dish.
Layer ⅓ of the tortillas over the sauce, covering the bottom
Add ½ of the meat mixture.
Add 1 cup of the cheese evenly over the meat.
Pour ½ cup of the enchilada sauce over the cheese.
Repeat the layers with ⅓ of the tortillas, the rest of the ground beef mixture, a cup of cheese and ½ cup of sauce.
Add the final ⅓ of tortillas on top of the casserole and pour the rest of the sauce over the top.
Sprinkle with the remaining cheese.
Cover the casserole with foil and bake for 30 minutes.
Uncover and bake for an additional 10 minutes or until cheese is melted and browned.
Sprinkle with green onions, cilantro, tomatoes, or other favorite toppings.
