Rinse cranberries and remove any soft berries.
Zest the orange, then peel and section, removing white pith.
Pulse cranberries in a food processor until chopped but not pureed.
Add orange sections and pulse until roughly chopped.
Transfer to bowl and stir in orange zest, sugar, and walnuts.
Let it sit for 30 minutes before serving to allow flavors to meld.
Refrigerate for up to one week.