In a large skillet over medium heat, brown the ground beef, breaking it apart with a spoon. Cook until no longer pink. Drain any excess fat.
Add the diced onion and minced garlic to the skillet and sauté for about 2-3 minutes until the onion becomes translucent.
Transfer the cooked beef mixture to the slow cooker. Add in the black beans, corn, diced tomatoes (with their juices), frozen bell peppers, chili powder, cumin, smoked paprika, salt, and pepper. Stir until fully combined.
Cover and cook on low for 6-8 hours or high for 3-4 hours.
About 15 minutes before serving, sprinkle the shredded cheddar cheese over the top of the casserole. Cover and allow the cheese to melt.
When ready to serve, gently crush the tortilla chips and scatter them over the cheese topping for a crunchy finish.