1. Preheat the oven to 350°F. Lightly coat a 9×13-inch baking dish with cooking spray.

2. To make the enchilada sauce, heat olive oil in a large skillet over medium heat. Add the diced onion and kosher salt. Cook for about 5 minutes until softened and translucent.

3. Stir in the cumin and chili powder. Cook for 30 seconds until fragrant, then sprinkle in the flour and stir well.

4. Slowly whisk in the chicken stock until smooth. Add the tomato sauce and minced garlic. Bring the sauce to a gentle simmer and cook for 5 minutes, stirring occasionally. Blend the sauce if you prefer a smoother texture.

5. In a separate skillet, cook the ground beef over medium heat. Season with salt and black pepper. Once the meat begins to brown, add the diced onion and continue cooking until the beef is fully cooked.

6. Drain excess grease from the beef mixture, then stir in the diced green chiles and black beans.

7. Spread 1/2 cup of enchilada sauce across the bottom of the prepared baking dish. Stir another 1/2 cup of sauce into the beef mixture.

8. Dip 6 tortillas into the remaining sauce to coat them lightly, then layer them across the bottom of the baking dish.

9. Spread half of the beef mixture over the tortillas and top with 1 cup of shredded cheese.

10. Dip the remaining tortillas in the sauce and place them over the first layer. Add the remaining beef mixture and finish with the remaining cheese.

11. Bake uncovered for 20 minutes, or until the cheese is melted and bubbly.

12. Let the casserole rest for a few minutes before slicing and serving.