Once the ground beef is cooked add in the taco seasoning as instructed on the package or use 2 Tbsp of Homemade Taco Seasoning and 1/4 Cup Water, stir this into the ground beef until it's fully coated.
Add the onion, beans, tomato sauce, and diced tomatoes into the skillet along with the beef. Let this simmer and cook on medium-high heat for 5 minutes.
Spray a 9x13 baking dish with nonstick cooking spray, and place 6 white corn tortillas on the bottom.
Top the tortillas with the meat mixture.
Coat with 1 cup of cheese.
Add another layer of tortillas (6 tortillas) and then again with the remaining meat.
At this point add an additional layer of tortillas, the final 6 tortillas.
Top evenly with the remaining cheese.
Baked at 350*F for 15 minutes.
After 15 minutes, if you want the cheese crispy on top, set it to broil on LOW for 3 minutes. Watch this closely.
Let cool for 5 minutes and serve.
Notes
This is made with white corn tortillas, it can be done with flour too but may change the cooking times.