Preheat the oven to 350°F (175°C).
In a medium bowl, combine graham cracker crumbs, melted butter, and granulated sugar. Stir until well combined.
Press the graham cracker mixture evenly into the bottom of a 9×13-inch baking pan to form the crust.
Pour the sweetened condensed milk evenly over the crust.
Sprinkle the chocolate chips evenly over the sweetened condensed milk layer.
Evenly distribute the shredded coconut over the chocolate chips.
Sprinkle the chopped walnuts evenly on top of the coconut layer.
Bake in the preheated oven for 25 minutes, or until the edges are golden brown.
Remove from the oven and allow the bars to cool completely in the pan on a wire rack.
Once cooled, cut into 16 bars and serve.