Cranberry Jell-O Mold

In a large bowl, dissolve gelatin in water. Stir in cranberry sauce and pineapple. Cover and refrigerate for 1 hour or until slightly thickened. Stir in nuts. Pour into a 1-1/2-qt. gelatin mold coated with cooking spray. Refrigerate until set. Unmold onto a serving platter. Serve with sour cream if desired.