Preheat oven to 350°F. Mix graham cracker crumbs and melted butter, and press into bottom of 9x12-inch pan.
Sprinkle butterscotch chips and then chocolate chips over crumb layer. Sprinkle nuts over chips. Sprinkle coconut next. Pour sweetened condensed milk over coconut, making sure it is spread evenly to the edges of the pan.
Bake for 25 minutes. Remove pan from oven and place on wire rack to cool for 5-10 minutes. Cut into squares and serve warm.