Cook yams or sweet potatoes in enough water to cover for 25 to 35 minutes or till just tender. Drain. Peel and cut into 1-1/2-inch-thick slices.
Finely shred enough orange peel to make 1 teaspoon; set aside. Remove and discard remaining peel from oranges. Cut oranges into thin slices. Alternate sweet potato and orange slices in a 2-quart rectangular baking dish.
In a small saucepan, combine sugar, margarine or butter, water, nutmeg, and salt. Bring to boiling; boil gently, uncovered, for 3 minutes. Stir in shredded orange peel. Pour mixture over potato mixture.
Bake, uncovered, in a 325 F. oven for about 30 minutes or till glazed, spooning syrup over potatoes once.
Before serving, spoon any syrup in baking dish over potatoes. Sprinkle pecans over top.