Melt butter in large pan. Add peanut butter. Melt until smooth. Add butterscotch chips. Melt until smooth. Pour cereal into liquid mixture and mix until well coated. Pour out onto a cookie sheet. Let cool about 1 hour.
Place mixture in a plastic bag (by cupfuls) with about 1/4 cup powdered sugar in it. Shake until "chow" is well coated. Continue mixing sugar and mix until done. Store in an airtight container. Fills 1 large Tupperware bowl.