Roast the bell pepper over a gas flame, turning with tongs, or broil until the skin is blackened. Transfer to a bowl, cover and let cool. Peel, seed and chop the pepper.
Heat the EVOO in a Dutch oven or other heavy pot over medium-high heat. Add the sausage and pancetta and cook until well browned. Add the ground pork, thyme, fennel seeds, garlic, chile peppers, onions, oregano and roasted red peppers and cook until soft, about 5 minutes. Stir in the tomato paste and cook for 1 minute. Deglaze with the wine, stirring and scraping up any browned bits from the bottom of the pot with a wooden spoon. Add 2 to 3 cups chicken stock and simmer for a few minutes to allow the flavors to combine.
Bring 2 cups chicken stock and the milk to a low boil in a saucepan. Whisk in the polenta and cook, whisking, until thick but pourable, 2 to 3 minutes. Remove from the heat. Add the butter and then the cheese, stirring until melted. Season with salt and pepper.
Ladle the polenta into shallow bowls and hollow out the center. Fill with the chili and top with more cheese. Garnish with parsley.
The chili can be covered and refrigerated for a make-ahead meal. Reheat over medium heat, and prepare the polenta before serving.