Place pecans in a single layer on a baking sheet coated with cooking spray; sprinkle evenly with sugar.
Bake at 350° for 8 to 10 minutes or until lightly toasted. Cool.
Stir together ice cream, 3/4 cup cookie chunks, and 1/3 cup pecans; spoon into piecrust. Freeze 10 minutes. Press remaining cookie chunks and pecans evenly on top. Cover with plastic wrap, and freeze 8 hours. Drizzle individual slices evenly with chocolate syrup.
Note: For testing purposes only, we used Keebler Chocolate Ready Crust, Häagen-Dazs Light Coffee Ice Cream, and Häagen-Dazs Light Dutch Chocolate Ice Cream.