Place the popcorn and peanuts in a large, greased mixing bowl. Melt the peanut butter, chocolate chips and butter in a small pan, over low heat, stirring until smooth.
Drizzle the chocolate mixture over the popcorn and nuts. Stir to coat evenly. Press 1/2 cup portions into muffin tins lined with foil muffin papers. Freeze until firm, about 1 hour. Makes 14-16 cups.