Using an electric mixer, beat the cream cheese and powdered sugar until smooth. Add the peanut butter, milk, and peanuts. Beat the mixture until smooth. Fold in half of the whipped cream into the peanut butter/cheese mixture. Set aside the remaining whipped cream in the refrigerator. Spoon the filling into the prepared pie shell. Refrigerate the pie for 1 hour or until the pie is set. Place a piece of pie in the center of a plate. Garnish the pie with the remaining whipped cream, chopped peanuts, chocolate shavings, chocolate sauce, powdered sugar, and mint sprigs.