Preheat your oven to 375°F (190°C) and gather all your ingredients. Prepare your 9x13 inch casserole dish by lightly greasing it.
In a large skillet over medium heat, brown the ground beef, breaking it apart with a wooden spoon. Add diced onions and cook until translucent. Season with salt, pepper, and garlic powder.
Begin layering the casserole. Start by adding a layer of enchilada sauce at the bottom of the dish, followed by corn tortillas. Add a layer of beef, black beans, cheese, and more enchilada sauce. Repeat these layers once more and finish with cheese on top.
Cover the casserole dish with aluminum foil and bake in the preheated oven for 20 minutes. Remove the foil and bake for an additional 5 minutes to let the cheese turn golden and bubbly.
Remove from the oven and let it cool slightly before serving. Garnish with your favorite toppings such as sour cream, jalapeños, or cilantro.
Notes
To store leftovers, place in an airtight container and refrigerate for up to 3 days, or freeze for up to 3 months. Reheat in the oven before serving for best results.