Sauté the onions and peppers. Place a large dutch oven or cast iron pot on your stove and pre-heat to medium heat. Drizzle the olive oil in the pan and add the diced onions and bell peppers. Cook for 5-6 minutes or until the peppers have softened and the onions are semi-translucent. Add in the garlic and cook for 1-2 minutes more.
Add remaining ingredients to the brisket chili. Add the chopped brisket to the pot and stir gently until the mixture is well combined. Add in the beans, tomatoes, and seasonings. Taste and add in any additional salt, pepper or other seasonings as needed. Stir until well combined.
Cook the brisket chili. Reduce the heat to low and cover. Allow the chili to cook for at least 30 minutes, or up to 2 hours, stirring occasionally.
Serve immediately. Serve the brisket chili with shredded cheese, diced onions, sour cream, or any other toppings that you like!
