Preheat oven to 400°F. Grease a pizza pan and spread out dough to fit. Bake for 10 minutes.
Remove from oven and spread Nutella over the cooked pizza dough leaving a gap around the edge. It will be very hot so be careful.
Sprinkle graham cracker crumbs over the chocolate. Top with a layer of mini marshmallows.
Put back in the oven for another 5 minutes, or until marshmallows are browned and crust is completely cooked to a golden brown. Serve hot. Refrigerate any uneaten portions.