Mix together the margarine, flour, and chopped pecans or walnuts until fully blended.
Pour the crust mixture into your baking pan and evenly and firmly press it into the bottom of your pan, forming an even crust.
Bake the crust in the 350-degree oven for 15 minutes, or until it turns a light golden brown.
Remove from the oven and let completely cool.
Cream Cheese Layer
Blend together the cream cheese and 1 1/2 cups of the Cool Whip.
When it's completely combined, spread it evenly over the cooled crust.
Pistachio Pudding Layer
In a large mixing bowl, whisk together the two boxes of pudding mix with 3 cups of milk. Let it thicken and place it in the refrigerator for 3-4 minutes.
Once it is thick and cool, evenly spread it onto the cream cheese layer.
Place in refrigerator for 15 minutes to chill.
Topping
Once the dessert is set and nice and chilled, top with Cool Whip.
Sprinkle with chopped pistachios. If you don't have pistachios on hand, you can also use chopped pecans or walnuts.
Place in the refrigerator for another 30 minutes until completely cool.