Preheat oven to 350. Prepare 28 standard muffin cups with cooking spray and flour; set aside. In a mixing bowl, combine margarine, brown sugar, eggs, flour, cinnamon, nutmeg, salt, and baking soda. Mix well. Fold in sour cream, cranberry sauce, and walnuts. Mix until smooth. Fill prepared muffin cups half full with batter. Bake for 25 minutes, or until done on the inside. Cool completely. Frost each cupcake evenly with frosting. Sprinkle tops with Christmas Mix sprinkles. Chill until ready to serve.