Preheat the oven to 350°F (175°C).
Combine graham cracker crumbs and melted butter in a bowl.
Press the mixture into the bottom of a greased 9x13 inch baking dish.
Bake the crust for 10 minutes, then let cool completely.
In a bowl, beat together softened cream cheese and powdered sugar until smooth.
Fold in the whipped topping and mini marshmallows gently.
Spread the filling over the cooled graham cracker crust.
Sprinkle chopped nuts and chocolate chips over the top.
Refrigerate for at least 4 hours or overnight to set before serving.