Heat 1 tablespoon olive oil over medium heat.
Cook onion and bell peppers until softened, about 5 minutes.
Add garlic, chili powder, and cumin. Cook 1 minute more.
Add lentils, beans, tomatoes, tomato sauce, and broth.
Bring to a boil, reduce heat to a simmer cook covered 25 minutes. Uncover and cook an additional 15 minutes or until chili reaches desired thickness.
