Prepare the crust: Mix the chocolate cookie crumbs, 1/4 cup sugar, and melted butter in a bowl until combined. Press the mixture firmly into the bottom and up the sides of a 9-inch pie plate. Chill the crust for at least 30 minutes.
Make the filling: In a large bowl, whisk together the instant chocolate pudding mix and cold milk for 2 minutes until slightly thickened. Stir in the vanilla extract.
Fold in half of the thawed whipped topping gently into the chocolate mixture until just combined.
Spread the chocolate filling evenly into the chilled crust.
Cover the pie loosely with plastic wrap, making sure the wrap does not touch the surface of the filling. Refrigerate for at least 4 hours, or preferably overnight, until the filling is firm.
Before serving, spread the remaining half of the whipped topping over the chilled filling.
Garnish the top with chocolate chips and holiday sprinkles for a festive look. Slice and serve cold.
Notes
For a make-ahead Christmas dessert, complete steps 1 through 4 one day before you plan to serve the pie. Keep it covered in the refrigerator.
If you prefer a homemade whipped cream topping, whip 1 1/2 cups heavy cream with 2 tablespoons powdered sugar and 1/2 teaspoon vanilla until stiff peaks form.
Use a food processor to quickly crush the cookies for the crust.