Pistachio Mallow Salad

1-16 oz. cool whip, thawed
1-3.4 oz pkg. instant pistachio pudding mix
3 c miniature marshmallows
6 to 7 drops green food coloring, optional
1-20 oz crushed pineapple, undrained
1/2 c chopped pistachios or walnuts

In a large bowl, combine whipped topping, pudding mix and food coloring if desired. Fold in the marshmallows and pineapple. Cover and refrigerate for at least 2 hours. Just before serving, sprinkle with nuts. Serves: 8-10