Pour melted butter over bottom of a 13x9x3-inch baking pan; sprinkle with graham cracker crumbs, mix, and press evenly over bottom of pan. Sprinkle crumb layer with chocolate chips then peanut butter chops. Pour sweetened condensed milk evenly over all. Sprinkle with chopped peanuts, then press lightly all over. Bake at 350° for 20 to 25 minutes, until set. Place pan on rack to cool then cut into bars.
Makes about 20 chocolate peanut butter bars.