Preheat the oven to 350°F. Spray the bottom of a 9 x 13 inch baking dish with cooking spray.
First layer: Combine graham cracker crumbs, ½ cup pecans, melted butter, sugar and cinnamon. Mix well. Press firmly onto the bottom of the baking dish. Bake for 22-25 minutes or until golden and set. set aside to cool completely.
Second layer: Cream together 8 ounces of cream cheese and 1 cup of powdered sugar. Fold in one third of the thawed whipped topping by hand. Spread over the crust and sprinkle with ¼ cup of toffee bits.
Third layer: Whip together both boxes of pumpkin spice pudding mix with 2 cups of cold milk for 3-4 minutes until thickened. Spread over the cream cheese layer.
Fourth layer: Frost the top with the remaining whipped topping. Sprinkle with a reserved pecans and toffee bits.
Chill for at least 4 hours or overnight. Cut into squares for serving.