Combine wafer crumbs and butter; press onto the bottom and up the sides of a 9-in. pie plate. Bake at 350° for 10 minutes. Cool.
Meanwhile, in a large bowl, cream the peanut butter, cream cheese and sugar. Add vanilla. Fold in whipped topping and 1/2 cup chocolate chips. Spoon into cooled crust; chill for several hours. Sprinkle remaining chocolate chips on top. Store in refrigerator.