Heat a large skillet over medium high heat. Add the ground beef and cook, breaking it up with a spoon, until browned and no longer pink, about 6 minutes. Drain excess fat if needed. Add the diced onion and minced garlic, and cook for 2 more minutes until fragrant.

Spray the inside of your slow cooker with non-stick spray. Start with half the beef mixture, then add half the black beans and corn. Sprinkle half the spices (chili powder, cumin, paprika, salt, pepper) over that layer. Then pour in half the tomatoes and half the beef broth. Repeat layers. Finally, stir in the uncooked rice gently.

Cover and cook on LOW for 4 to 5 hours or on HIGH for 2.5 to 3 hours. The rice should be tender and the liquid mostly absorbed. About 30 minutes before serving, stir the casserole once. Taste and adjust salt. Then sprinkle the shredded cheese and crushed tortilla chips evenly over the top. Replace the lid and let it melt for 15 minutes.

Turn off the slow cooker. Spoon the casserole into bowls. Top with fresh cilantro, a dollop of sour cream, and extra tortilla chips for crunch.