Place the cookies in a food processor and process until they are completely pulverized. (You should have about 1 1/2 cups of crumbs.) Pour the crumbs into a bowl and stir in the sugar.
Pour the melted butter over the crumbs and stir to combine. The mixture will fill wet. Pour the mixture into a 9-inch pie dish and press into the bottom and up the sides. It's often easiest to use the bottom of a measuring cup to press the mixture in firmly. Refrigerate the crust until needed again.
Make the peanut butter filling:
Place the chocolate chips in a microwave safe bowl and melt on 50% until melted. Alternately, melt the chips in a double boiler. Add the corn syrup and stir to combine.
Remove the crust from the refrigerator and using a spatula, spread the chocolate in an even layer on the bottom of the crust. Return the crust to the refrigerator.
Place the cream cheese, peanut butter, vanilla and brown sugar in the bowl of an electric mixer fitted with the paddle attachment. Turn the mixer on to medium and beat until the mixture is combined and smooth, scraping down the sides of the bowl as needed. Set aside.
Place the cream in a clean bowl and beat with a whisk until soft peaks form.
With a spatula, gently fold the whipped cream into the peanut butter mixture, folding until there are no white streaks. Pour the mixture into the prepared crust and freeze for at least 4 hours.
Once the pie is frozen, you can tightly cover it with foil and freeze up to 3 hours.
Make the hot fudge sauce:
Place the milk chocolate and dark chocolate in a medium heatproof bowl. Set aside
Place the cream in a small saucepan and bring it to a simmer over medium heat. Add the corn syrup and stir. Remove the mixture from the heat and pour it over the chocolate. Let it sit for 2 minutes, then stir until completely smooth and melted.
You can refrigerate the hot fudge sauce in a covered container for up to 3 days. Warm the sauce before drizzling over the pie to serve.