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. Drain excess fat and transfer to your crockpot.
Add diced onion, green bell pepper, red bell pepper, and minced garlic to the crockpot with the beef.
Add kidney beans, black beans, diced tomatoes, tomato paste, and tomato sauce.
Pour in the beef broth and sprinkle in chili powder, cumin, smoked paprika, oregano, cayenne, salt, black pepper, and brown sugar if using. Stir everything well to combine.
Cover and cook on low for 6-8 hours (or high for 3-4 hours), stirring once halfway through if you can.
Taste and adjust seasonings as needed. Serve hot with your favorite toppings like shredded cheese, sour cream, and chopped green onions.
Notes
Serve with your favorite toppings for a delicious chili experience.