Preheat oven to 350°F (175°C). Lightly grease a 9x13-inch pan or line with parchment paper.
Pour melted butter into the pan. Sprinkle graham cracker crumbs evenly, pressing down to form a crust.
Pour sweetened condensed milk evenly over the crust to create a sticky base layer.
Sprinkle chocolate chips, butterscotch chips, walnuts, and shredded coconut evenly over the milk layer.
Bake for 25–30 minutes, or until golden brown and coconut is toasted.
Cool completely before slicing into bars for clean edges.