Prepare vegetables by dicing the onion and mincing garlic.
Brown ground beef with onions and garlic in a pan over medium heat. Break apart the meat as it cooks.
Drain any grease and transfer the mixture to your crockpot.
Add kidney beans, black beans, diced tomatoes, and tomato sauce to the slow cooker.
Pour in beef broth and sprinkle chili powder, cumin, smoked paprika, salt, and pepper. Stir thoroughly.
Cover and cook on LOW for 4 hours (or HIGH for 2–2.5 hours).
Add elbow macaroni directly into the crockpot. Stir so pasta is submerged.
Cook for 15–20 minutes or until pasta becomes tender.
Add cheddar and mozzarella cheese and stir until melted.
Taste and adjust seasoning as needed before serving.