Preheat oven to 350 degrees. Spray standard pie dish (not a deep dish pie dish) with nonstick spray. Set aside.
Process Oreo cookies until they turn into fine crumbs. Measure out 2 cups. Discard the rest of the crumbs. Add melted butter to 2 cups of crumbs and stir together until combined. Place into prepared pie dish. Using your fingers, press crumbs firmly into an even layer in the pie dish and up the sides. Bake in preheated oven for 8 minutes. Remove from oven and let it cool completely.
Add ½ cup heavy cream and granulated sugar to a bowl fitted for a stand mixer. With the whisk attachment, beat cream until stiff peaks form. Remove whipped cream and place into a small bowl. Add cream cheese, peanut butter, and powdered sugar to bowl. Using a paddle attachment, mix ingredients until combined.
Gently fold whipped cream into the peanut butter mixture so it doesn't deflate. Stop when white streaks of cream are no longer present. Spread mixture into cooled pie crust. Smooth the top into a flat, even layer. Place in refrigerator to chill for at least 2 hours.
Make milk chocolate ganache by first heating up cream to a scalding level (right before boiling point). Pour hot cream over milk chocolate and let sit for 8 minutes. Stir together to combine into a shiny ganache. Pour over pie until you reach desired thickness on top. I like a thin layer, but lay it on thick if you want all the chocolate! Chill until chocolate firms up, about 1 hour. Cut and serve.