Heat a skillet over medium heat. Add the ground beef, diced onion, and minced garlic. Cook until the beef is browned and the onion is soft. Drain any excess fat.
Stir the chili powder and cumin into the beef mixture and cook for one more minute.
Pour a thin layer of enchilada sauce into the bottom of the slow cooker. Add half the torn tortillas, half the beef mixture, half the black beans, half the corn, and one cup of cheese. Repeat the layers with the remaining ingredients, ending with cheese on top.
Cover and cook on low for 4 hours or until the casserole is heated through and the cheese is melted.
Sprinkle with chopped cilantro before serving.