In a large Dutch oven or stockpot, heat olive oil over medium heat. Add the onion, carrot, celery, sweet potato and garlic, and cook over medium heat for 6 to 8 minutes, or until vegetables start to soften.
Add the beans, corn, green chilies, tomatoes and vegetable stock, and simmer over medium-high heat.
Add the vinegar, brown sugar, chili powder, cocoa powder, cayenne, salt and black pepper. Stir until well mixed.
Reduce heat to medium-low and simmer for 20-30 minutes. Ladle into bowls and serve with your favorite toppings.