Melt butter in microwave-safe bowl and add the graham cracker crumbs to it. Stir to combine and press crumb mixture into a foil-lined and cooking sprayed 9 x 13 pan (foil is optional but will really save with cleanup time)
Pour sweetened condensed milk evenly over crumb mixture.
Layer evenly with half the chips, i.e. 1/2 c of each kind of chip, then top with half the amount of coconut, i.e. about 3/4 c. Then add the rest of the chips and rest of the coconut. I did this so that the chips were evenly dispersed within the fluffiness of the coconut. But you don’t have to be so precise.
After the chips and coconut are layered in, add the the toffee bits (or nuts) to the top.
Bake at 350F for 30 minutes, or until top is barely browning. Start checking on it after 25 minutes. Allow to cool and slice. You can store extras in the freezer in case you want to make these ahead for unexpected company. Or unexpected munchies.