Clean and pick thru cranberries. Slice unpeeled orange into eights, remove seeds. Place half the cranberries and half the orange slices in food processor. Process until evenly chopped. Transfer to a bowl. Repeat with remaining cranberries and orange slices. Transfer to the other processed fruit. Stir in sugar. Can add 1/2 cup chopped nuts if desired.
After sugar dissolves store in refrigerator. Keeps for up to two weeks in refrigerator.