Stir together melted butter and graham cracker crumbs, and press into bottom of a 13- x 9-inch pan.
Pour sweetened condensed milk over crumbs; sprinkle evenly with chocolate and butterscotch morsels, coconut, and walnuts. Gently press mixture to a uniform thickness with a fork.
Bake at 350° for 25 to 30 minutes or until coconut is lightly browned. Cool 45 minutes on a wire rack. Cut into 1 1/2- x 2 1/2-inch bars.