Line a 10-by-13-inch pan, 2 inches tall, with parchment paper, leaving some hanging over the sides of the pan (for removing later). Set aside.
Preheat oven to 325℉.
Finely grind the Oreos, then add in the chopped pecans and melted butter. Mix well, then press into bottom of prepared pan. Bake for 6 minutes. Remove from oven and let cool.
Melt ganache and pour over chocolate crust and spread evenly.
Drizzle caramel sauce over ganache and then sprinkle the chopped hazelnuts on top. Place pan in the freezer for at least 30 minutes.