In a skillet over medium heat, brown the ground beef until fully cooked. Drain any excess fat.
Transfer the cooked ground beef to the crockpot.
Add the diced onion, minced garlic, and diced bell pepper to the crockpot.
Stir in the diced tomatoes (with juice), kidney beans, and beef broth.
Season with chili powder, cumin, salt, black pepper, and paprika. Mix well to combine all the ingredients.
Cover and cook on low for 6 hours or on high for 3 hours, until the flavors meld together and the vegetables are tender.
Serve hot, topped with optional shredded cheese, sour cream, and chopped green onions, if desired.