Preheat the oven to 350°F (175°C).
In a bowl, mix flour, butter, and pecans until crumbly.
Press the mixture into a 9x13-inch baking dish.
Bake for 15–20 minutes until lightly golden. Cool completely.
In another bowl, beat cream cheese and powdered sugar until smooth.
Fold in 8 oz of whipped topping and spread over the cooled crust.
Whisk together pudding mix and cold milk until thickened.
Spread pudding over the cream cheese layer.
Top with remaining whipped topping.
Chill for at least 4 hours or until set.