Preheat oven to 350 degrees Fahrenheit (325 degrees Fahrenheit if using a glass pan.)
Melt butter in a 9-by-13 inch baking dish and sprinkle on graham cracker crumbs. Press down lightly to form a crust.
Sprinkle, in layers, the coconut, nuts, butterscotch chips and chocolate chips.
Drizzle condensed milk evenly over the top, trying your best to avoid getting any on the inside of the pan.
Place in preheated oven and bake for 25-30 minutes.
Cool completely before cutting into bars. You may want to refrigerate the bars once they have cooled slightly to speed the process along and prevent the bars from becoming too crumbly.
Keep in a resealable container either at room temperature (if it’s not too warm wherever you are) or in the refrigerator.