Combine flour, 1/2 cup pecans and butter in a medium bowl and mix well. Press onto the bottom of an 11 x 8-inch baking dish. Bake until lightly browned, about 15 minutes. Let stand to cool.
Place cream cheese in a medium bowl. Beat with an electric mixer set at medium speed until fluffy. Add confectioners' sugar and beat until mixture is light and fluffy.
Add 1 cup whipped topping to cream cheese mixture and fold in gently. Spread over cooled crust.
Combine pudding mix and milk in a medium bowl. Beat until thickened. Spread on top of cream cheese layer. Top with the remaining whipped topping. Sprinkle with remaining pecans. Chill, covered, for 1 hour. Store any leftovers in the refrigerator.