Preheat the oven to 350 degrees (325 degrees for glass dish). In a 13 x 9 inch baking pan melt butter in oven.
Remove the pan with melted butter from the oven and sprinkle the graham cracker crumbs over top of the melted butter.
Stir together then press into the pan to form a crust layer.
Pour the sweetened condensed milk evenly over top of the graham cracker crust.
Sprinkle evenly with the peanut butter chips, peanut butter cups, coconut, and walnuts. Press down firmly to pack ingredients. Bake 30 minutes, or until lightly browned. Cool completely before cutting.