Preheat oven to 350 degrees. Spray a 9x13 baking dish.
Combine flour, butter, and 1/2 Cup pecans. Press evenly into greased 9x13 dish. Bake for 15 minutes. Let cool completely.
Mix cream cheese and powdered sugar. Add 1/2 container of whipped topping. Spread evenly over crust.
Mix milk and vanilla instant pudding, add pumpkin puree and cinnamon. Mix until well combined. Spread evenly over cheesecake layer.
Refrigerate for one hour.
Spread remaining 1/2 container of whipped topping evenly over pumpkin layer. Sprinkle with 1/4 Cup chopped pecans.
Store in refrigerator.