Add oil, onion, green and yellow bell pepper, and garlic to a large pot over medium-high heat. Stir and cook until tender, about 3 minutes. Stir in tomatoes, broth, and chili powder. Cook for 10 minutes, stirring occasionally.
Lower heat to medium-low. Add all of the beans, salt, and black pepper. Cover the pot and simmer for 20 minutes. For spicier chili, add crushed red chili flakes.
Ladle chili into bowls and garnish with cilantro.
YIELD: 6 servings I PREP TIME: 15 min I COOK TIME: 35 min I TOTAL TIME: 50 min