Heat a large skillet over medium heat and cook ground beef until browned. Add onions and garlic; cook until onion is translucent. Drain excess fat if necessary.
Add black beans, diced tomatoes, and green chilies. Stir in chili powder and cumin, then season with salt and pepper. Simmer for 8-10 minutes.
Preheat oven to 375°F (190°C) and grease a 9x13-inch baking dish.
Spoon beef mixture into the baking dish. Prepare cornbread mix and pour evenly over beef.
Bake for 25-30 minutes, until the cornbread is golden brown. Allow the pie to rest for 10 minutes and top with cheese and cilantro before serving.
Notes
Leftovers can be stored in a sealed container and refrigerated for up to 4 days. Freeze for up to 2 months for extended storage.