Cook potatoes in boiling, salted water until just tender. Cool and skin. Slice 1/2 inch thick. Slice whole orange very thin, removing seeds. Place layers of sweet potatoes and orange slices in buttered casserole, sprinkling each layer with sugar.
Brown seasoned chops in hot skillet; lay on potatoes. Add 3 tablespoons water. Cover and bake in moderate oven 1 hour. Baste occasionally with syrup in dish.