In a small bowl, mix Oreo crumbs and melted butter. Press the mixture into the bottom of a 13x9 dish. Place the crust in the freezer for 20 minutes.
Using an electric hand mixer, blend cream cheese and powdered sugar in a large bowl until smooth. Add 8 ounces of whipped topping and mix at low speed until well combined.
In another large bowl, whisk together the chocolate pudding mix and cold milk for about 2 minutes until thick. Let it rest for an additional 2-3 minutes to thicken further.
Take the crust out of the freezer and spread the cream cheese mixture evenly over it. Sprinkle 1/2 cup of chopped pecans on top and gently press them into the cream cheese layer.
Spread the chocolate pudding over the cream cheese and pecan layers. Finish by spreading the remaining 8 ounces of whipped topping over the chocolate pudding. Cover with plastic wrap and refrigerate for at least 4 hours, preferably overnight.
Before serving, drizzle caramel sauce and chocolate syrup over the dessert. Sprinkle the remaining 1/2 cup of chopped pecans on top. Slice and serve chilled.
Notes
For a nut-free option, omit the pecans or substitute with crushed cookies for added texture.