Add the potatoes to a large pot, cover with water and bring to a boil over medium heat. Salt the water and cook to tender about 12 to 15 minutes. Drain and return to hot pot. Add the zest, butter, creme fraiche or sour cream, salt, pepper and nutmeg, to taste.
While potatoes are coming to a boil, heat a chili pot with extra-virgin olive oil, 2 turns of the pan, over medium-high to high heat. Add the turkey and brown, then add in the onions and cook 2 to 3 minutes. Chop the peppers, then add them along with the garlic to the turkey. Stir in the spices, and add salt and pepper, to taste. Cook for 8 to 10 minutes, then add the tomato paste and cook for 1 minute. Stir in the stock and simmer a few minutes to thicken and combine flavors.
Preheat the broiler.
Transfer the chili to a casserole, spread the potatoes over the top and cover with Cheddar cheese. Brown under the broiler until golden and serve.