Place 1 package gelatin in large bowl and stir in 1 cup boiling water until gelatin is dissolved. Add cranberry juice. Cool about 15 minutes, then add cranberry sauce. Pour mixture into a 13-by-9-by-2-inch baking dish and let set until firm in the refrigerator.
In a small bowl, combine remaining package of gelatin and remaining 1 cup boiling water; stir until gelatin is dissolved. Let cool about 15 minutes, then add sour cream and walnuts.
When first layer is firm, spread second layer on top and refrigerate until set, at least 1 hour. Cut into squares before serving. Makes 8 to 10 servings.
This recipe is virtually fat-free since the only fat in it is from the walnuts.