Preheat the oven to 350 degrees. Coat a 9 x 13-inch baking dish with cooking spray and set aside.
In the bottom of a large skillet with a lid, heat the oil. Add the ground beef, onion, and garlic and cook for about 5 minutes, stirring occasionally, until the meat begins to brown.
Add the tomatoes, cover and cook for 5 minutes.
Add the beans and chili powder, stirring well to mix.
Pour half of a can of the enchilada sauce in the bottom of the prepared baking dish. Tear 8 of the tortillas into rough strips and cover the sauce. Top with the meat mixture.
Pour a full can of the enchilada sauce over the meat. Tear the remaining 8 tortillas into rough strips and cover the meat. Top with the remaining 1/2 can of enchilada sauce.
Sprinkle with the cheese and bake for 25 minutes, until the cheese begins to melt and the sauce begins to bubble.