In a large bowl, whisk the Oreo pudding mix and the milk together until thick and creamy, about 2 minutes. Fold in the coarsely chopped Oreo cookies and the Cool Whip until completely combined and smooth.
Spread into the prepared pie crust and refrigerate for at least 8 hours or until firm and set. Just before serving, decorate the edge of the pie with the miniature Oreo cookies and drizzle the pie with chocolate syrup.
*Note: If you cannot find the Oreo pudding mix, feel free to use instant vanilla pudding mix or white chocolate pudding mix (3.4-ounce) and proceed with the recipe as normal.