Preheat oven to 350 degrees F. Spray a 9x13-inch baking pan with non-stick spray. Set aside.
Prepare chocolate cake according to box directions. Bake as directed until toothpick inserted in center comes out clean. Cool cake for 10 minutes.
Poke holes all over the cake, at least 1 inch apart with the handle of a wooden spoon or spatula.In a medium bowl, add both Instant Oreo pudding mixes and milk. Whisk until it's all combined and thickened. This will take about one minute or so. (It will be a little lumpy because of the Oreos in the pudding mix.)
Pour pudding all over the warm cake; using the back of a spoon to spread it evenly all over the cake and gently pushing down into the holes.Spread the whipped topping evenly over the pudding. Then top with crushed Oreo cookies.
Place cake in the refrigerator and let chill for at least one hour before serving.Cut into slices, serve and enjoy!