Melt butter; stir in crushed graham crackers. Pat crumb mixture evenly in bottom of an ungreased 13x9x2-inch baking pan. Layer, in order, chocolate pieces, butterscotch pieces, coconut, and walnuts. Pour sweetened condensed milk evenly over all.
Bake in a 350 degree oven 30 minutes; cool. Cut into bars. Makes 36 to 48.