1.Preheat the oven to 350 degrees F. Spray a 9x13-inch pan or 2-quart baking dish with nonstick spray.
2.In a large skillet, cook the ground beef and onion together over medium heat until the beef is browned and the onion is tender. Drain any fat, if needed. Stir in the chili powder, cumin, beans, and chiles; set aside.
3. In a medium bowl, whisk together the sour cream, flour and garlic.
4. Place half of the tortillas in the bottom of the prepared dish to cover the bottom. Top with half of the meat mixture, spoon half of the sour cream mixture on top of the meat, and drizzle 3/4 cup of the enchilada sauce on top of that. Repeat the layer.
5. Cover with foil and bake for 30 minutes. Uncover, sprinkle with cheese and bake 15 minutes or so more, until the cheese is nice and bubbly. Serve immediately.
Notes: Can be frozen after step number 4. Can use pinto beans, canned or homemade. Serve with guacamole, a side salad, rice or corn. Serve condiments such as salsa, pico de gallo, or sour cream and slices of lime.