Preheat the oven to 350 degrees F. Grease an 8x8 baking pan with butter or cooking spray. In a small bowl, combine melted butter with graham cracker crumbs and press onto bottom of pan to form a crust.
Spread shredded coconut on top of graham cracker crust and layer with chocolate and peanut butter chips. Pour condensed milk over top and sprinkle with chopped walnuts.
Bake for approximately 25-30 minutes. When you remove from the oven, the mixture will still appear underbaked (milk layer will look as though it hasn't set). Place the bars in the refrigerator for 30 minutes up to an hour and remove them to cut. Serve in an airtight container in a cool, dry place for up to three days (but my guess is that they won't last that long).
Makes 12-16 bars (you might want to cut them into smaller pieces because they're so sweet).
Recipe by In Good Taste at https://ingoodtaste.kitchen/seven-layer-magic-bars/