Scrub and dry the potatoes. Cut a small, deep slit in the top of each potato. Set the potatoes on the middle rack of a preheated 375øF. oven and bake for about 1 hour, or until potatoes are tender when pierced with a fork.
Let potatoes cool slightly, cut off the tops and scrape the potato pulp into a bowl. So not scrape so deeply that you tear the potato skin. Salt and pepper the potato shells; reserve.
Mash the potato pulp and stir in 4 Tbs chopped olives, diced green chilies, and enough heavy cream to give the mixture the desired consistency. Season to taste with salt and pepper, and stir in 1/2 cup grated cheese.
Divide the potato mixture equally among the shells, mounding the filling slightly. Sprinkle with additional grated cheese and place on baking sheet.
Bake again at 400øF., until potatoes are hot and cheese is bubbling.
Top each potato with a generous dollop of sour cream, and add a black olive if you like. Serve immediately.