Preheat your oven to 350°F and lightly grease a 9x13 inch baking dish. While the oven heats, dice the yellow onion and green bell pepper into bite-sized pieces, mince the garlic, and cut the corn tortillas into 1-inch strips. Rinse and drain the black beans to remove excess sodium. Have all ingredients prepared before cooking.
Heat a large skillet over medium-high heat and add the ground beef, breaking it apart as it cooks. Once browned, add diced onion and green bell pepper, stirring occasionally until softened and beef is cooked through (about 8-10 minutes total). Drain off any excess fat.
Return the skillet to medium heat and add the minced garlic, cumin, and chili powder, stirring for about 30 seconds until fragrant. Pour in the red enchilada sauce, add the black beans and corn, stirring to combine. Bring to a boil, then reduce to medium-low and simmer for 10 minutes.
Spread a thin layer of meat sauce in the baking dish, arrange 6 tortilla strips over it, then spread half of the meat sauce over tortillas and sprinkle with half of the cheese. Repeat with another layer of tortilla strips and remaining meat sauce, reserving cheese for top.
Bake for 20 minutes until heated through and edges bubble. Remove and sprinkle remaining cheese on top, then bake for an additional 5 minutes until cheese is melted and golden. Let the casserole rest for 5 minutes before serving.