Make the crust: Preheat the oven to 350 degrees F. Butter a 9-inch pie plate. Pulse the graham crackers and peanuts in a food processor until finely ground. Add the melted butter and pulse to combine. Press the crumb mixture into the bottom and up the side of the prepared pie plate. Bake until set, 10 to 12 minutes. Transfer to a rack to cool.
Meanwhile, put the chocolate chips in a microwave-safe bowl and microwave at 50 percent power in 30-second intervals, stirring after each, until melted and smooth. Spread evenly in the prepared crust with a small offset spatula or the back of a spoon; set aside until the chocolate sets, about 10 minutes.
Make the filling: Beat the heavy cream in a bowl with a mixer on medium-high speed until soft peaks form; refrigerate until ready to use. In another bowl, beat the peanut butter, cream cheese, milk and vanilla on medium-high speed until smooth, about 1 minute. Add the confectioners' sugar and mix on low speed until incorporated.
Gently fold half of the whipped cream into the peanut butter mixture until combined, then fold in the rest. Spoon into the prepared crust and smooth the top. Cover with plastic wrap and refrigerate until set, at least 3 hours or overnight. Top with shaved chocolate before serving.