Heat the olive oil in a large Dutch oven over medium-high heat, then add the chopped onion and cook for about 2 minutes until it begins to soften. Add the ground beef and continue cooking until browned, breaking it apart as it cooks, which should take about 5 minutes. Drain off any excess grease, then stir in the minced garlic and cook for 30 seconds.

Next, add the chili powder, cumin, brown sugar, oregano, salt, black pepper, and tomato paste. Stir well to coat the meat and onions in the seasonings. Pour in the beef broth, scraping up any browned bits from the bottom of the pot to build flavor. Add the fire-roasted tomatoes and both types of beans, stirring until everything is fully combined.

Bring the chili to a boil, then reduce the heat to low and let it simmer gently for 1 to 2 hours, stirring occasionally. Keep the pot covered during the early cooking period to retain moisture, then uncover during the last 30 minutes if you would like the chili to thicken. Once the chili has reached your desired consistency, ladle it into bowls and serve with your favorite toppings.