Heat oil in large saucepan. Add onions and garlic, cook until lightly browned. Add bell peppers, cook for 5 minutes. Stir in water, tomatoes, sweet potatoes, beans, chiles, tomato sauce, chili powder and cumin.
Cook over medium heat for 20 to 25 minutes or until thickened and potatoes are cooked through. Season with salt and ground black pepper.