Combine sugar, water, port (or wine), cinnamon and nutmeg in a medium saucepan; bring to a boil. Add cranberries and cook for 1 minute. Stir in cranberries, return to a boil. Reduce heat and simmer until about half the cranberries pop, 10 to 12 minutes. remove from the heat.
Stir in walnuts and orange zest. Let cool completely. ( The marmalade will thicken as it cools.)
Serve at room temperature or chilled. Makes 4 cups.
(Leftovers are great on a turkey sandwich or with vanilla yogurt.)