Place the chocolate wafers in the bowl of a food processor and pulse until finely ground. (You should have about 2 1/4 cups crumbs.)
In a large bowl, stir together the chocolate crumbs and butter until thoroughly combined. Transfer the crumbs to a 10-inch (6-cup capacity) pie plate, and using the bottom of a cup, press the crumbs into the dish and up the sides to form the crust. Refrigerate crust while you prepare the filling.
In a medium saucepan over medium-low heat, combine the milk and sugar, stirring just until disolved. Whisk in the peanut butter and vanilla until mixture is smooth and creamy. Transfer the mixture to a large bowl.
Beat the well-chilled heavy cream in the bowl of a stand mixer fitted with the whisk attachment until stiff peaks form.
Fold the whipped cream into the peanut butter mixture.
Slice the banana into rounds and arrange them in a single layer on the bottom of the cookie crust.
Pour the peanut butter mixture over the bananas, smoothing with a spatula, and then top with the chopped salted peanuts.
Freeze pie, uncovered, until solid, about 5 hours. Slice and serve.
I prefer the classic Famous Chocolate Wafers for making cookie crusts, however any brand of chocolate wafers will work. You could even use Oreos, scraping out the filling and reserving it for another use (like eating it with your fingers).