In a medium mixing bowl, combine pecans, flour and butter. Press mixture into the bottom of a 9-inch springform pan. Bake for 20 minutes, then allow crust to cool.
In the bowl of a stand mixer fitted with a paddle attachment, beat the cream cheese and sugar until well blended. Stir in 1 1/2 cups Cool Whip. Spread the mixture over the crust.
Replace the paddle attachment with the whisk attachment. Beat pudding and milk, about 2 minutes. Spread pudding mixture over the layer of cream cheese.
Refrigerate the cake until firm, about 4 hours.
When ready to serve, run a knife around the edges of the springform pan to loosen the pie. Remove the rim, and transfer the pie to a serving dish. Top dessert with remaining Cool Whip before serving.
