Peel baked potatoes. Set two aside for later use in recipe. Chop two into bite sized chunks. In medium sized saucepan heat oil and saute onion until tender. Add bite size potatoes, salt and pepper to taste and saute for one to two minutes or until potatoes are heated through. In blender or food processor blend remaining potatoes and warm chicken broth until smooth. Add to saucepan and add sour cream and nutmeg. Heat through and serve with optional toppings if desired. Serves 4.