In a medium bowl, mix together melted butter and graham cracker crumbs until well combined. Press crumb mixture into the bottom of a 9x13-inch pan.
Spread coconut evenly over crust. Layer pecans, semi-sweet chips, butterscotch chips, dark chocolate chips, and M&M's evenly over coconut layer. Drizzle condensed milk evenly to cover chip layer. Bake in preheated oven for 20 minutes or until golden around edges. Cool completely before slicing into bars.