magic bars recipe

1/2 cup unsalted butter, melted - 1 1/2 cups graham cracker crumbs - 1 cup sweetened shredded coconut - 1 cup semisweet chocolate chips - 1 cup butterscotch chips - 1 cup chopped nuts (such as walnuts or pecans) - 1 can (14 ounces) sweetened condensed milk