In a Dutch oven, heat oil over medium-high heat. Add mushrooms, onions, red and green peppers, brown sugar, chili powder, garlic, and cumin; cook and stir until vegetables are tender. Add tomato paste; cook and stir 3-4 minutes or until slightly caramelized.
Stir in beans, tomatoes, broth, lime juice, cilantro, chipotle peppers, and seasonings. Bring to a boil. Reduce heat; simmer, uncovered, 8-10 minutes or until slightly thickened, stirring occasionally. Serve with toppings as desired.