Bring orange juice, water, sugar and cranberries to a boil in a medium saucepan over high heat.
Cook on medium-low for 10 minutes.
Take the saucepan off the stove.
Stir in mandarin oranges and walnuts.
As the sauce cools it will thicken.
Serve cold or at room temperature.
This is one item you can make ahead of time for the holidays and keep in the refrigerator.
Keeps well for 2 weeks in the fridge.