In a large pot, heat the oil over medium. Add the bell pepper, onion and garlic; season with salt and pepper. Cook, stirring occasionally, until the vegetables start to soften, about 3 minutes. Stir in the chili powder; cook until fragrant, about 1 minute. Add the sausage and cook, using a whisk to break up the meat, until browned, 5 minutes. Add the tomatoes and their juices, and the stock and beans; bring to a simmer. Cover and cook over medium-low until the flavors meld, about 1 hour. Season.
Divide chili among bowls; top with the Parmesan and parsley.