In a skillet over medium heat, brown the ground beef (or turkey) until fully cooked. Drain excess fat and transfer it to the crockpot.
Add the rinsed kidney beans, black beans, diced tomatoes (with juice), tomato paste, chopped onion, chopped bell pepper, and minced garlic to the crockpot.
Sprinkle in the chili powder, cumin, paprika, salt, and pepper. Pour in the beef broth or water.
Stir all ingredients together until well combined.
Cover and cook on low for 6 hours or on high for 3 hours.
Once it's done cooking, give it a good stir and taste for seasoning, adjusting if necessary.
Serve hot, garnished with cheese, sour cream, or green onions if desired.