In a large dutch oven, heat the olive oil over medium heat.
Add the onions and cook, stirring occasionally, until softened and translucent, about 5 minutes. Stir in the garlic and cook for 1 more minute, until fragrant.
Reduce the heat to low and stir in the peppers, sweet potatoes, chili powder, cumin, oregano, thyme, salt, chipotle chile and tomato paste.
Stir in the beans, tomatoes, and stock.
Simmer on low heat, uncovered, for about an hour, until thickened. Season with additional salt to taste.
Serve with desired toppings.