Mix Crust Ingredients: In a medium bowl, combine the graham cracker crumbs, sugar, and melted butter. Mix until the crumbs are evenly coated.
Press into Pie Dish: Press the mixture firmly into the bottom and up the sides of a 9-inch pie dish. Chill in the refrigerator while preparing the filling.
Prepare the Filling:
Make Pudding Mixture: In a large bowl, whisk together the instant vanilla pudding mix, eggnog, nutmeg, and vanilla extract. Whisk until smooth and thickened (about 2-3 minutes).
Fold in Whipped Topping: Gently fold in 1 cup of whipped topping until fully combined.
Assemble the Pie:
Add Filling to Crust: Pour the filling into the prepared crust and smooth the top with a spatula.
Chill: Refrigerate the pie for at least 4 hours, or until set.
Garnish and Serve:
Add Topping: Before serving, spread or pipe additional whipped topping over the top of the pie. Sprinkle with nutmeg or cinnamon for garnish, if desired.