Preheat oven to 350°F. Lightly coat a 13×9-inch baking dish with nonstick cooking spray.

In a medium bowl, combine self-rising flour, chopped toasted pecans, and melted butter. Mix until well combined.

Press the mixture evenly into the bottom of the prepared baking dish to form the crust.

Bake for 20 minutes, or until the crust is set and lightly golden. Remove from oven and allow to cool completely.

In a separate bowl, beat softened cream cheese and powdered sugar until smooth. Fold in 1 cup of the thawed whipped topping.

Spread the cream cheese mixture evenly over the cooled crust.

In another bowl, whisk together whole milk, chocolate instant pudding mix, and vanilla instant pudding mix until thickened.

Spread the pudding mixture evenly over the cream cheese layer.

Top with the remaining whipped topping, spreading it evenly over the pudding layer.

Drizzle with chocolate syrup, if desired.

Refrigerate for at least 2 hours, or until set.

Slice and serve chilled.