For the filling: Grease a 9-by-13-inch pan with some butter.
Using a stand or electric hand mixer, mix together the butter and chunky peanut butter until smooth. Stir in the sugar a cup at a time.
Add the vanilla wafers to a food processor and process until they are in crumbs. Then add the crumbs and mini chocolate chips to the peanut butter mixture. Spread it evenly into the buttered pan and set aside.
For the frosting: Using a double boiler or a microwave, melt the chocolate chips and creamy peanut butter. Allow to cool for a couple of minutes, then pour over the base. Spread the frosting out evenly and sprinkle over the chopped peanuts. Refrigerate for at least 1 hour, then cut into 20 bars.