Heat a large Dutch oven or heavy-bottomed stockpot over medium-high heat.
Add the ground beef, chopped onion, and green bell pepper. Cook for 8–10 minutes, breaking the beef into crumbles as it cooks, until the meat is browned and the vegetables have softened. Drain any excess grease if needed.
Stir in the minced garlic, chili powder, paprika, cumin, onion powder, garlic powder, oregano, salt, black pepper, and cayenne (if using). Cook for 30–60 seconds, stirring constantly, until the spices become fragrant.
Add the fire-roasted diced tomatoes, tomato paste, beef broth, Worcestershire sauce, and brown sugar (if using). Stir until the tomato paste is completely incorporated.
Bring the chili to a gentle boil, then reduce the heat to low. Cover and simmer for 35–45 minutes, stirring occasionally, until the chili has thickened and the flavors have melded together.
Taste and adjust the seasoning with additional salt, pepper, or chili powder if desired.
Ladle into bowls and serve with your favorite toppings.