Bake brownie batter. In a large bowl mix up the brownie batter following instructions on the box of brownie mix. Pour the batter into the pizza pan. Bake according to box instructions for a 13×9 inch brownie pan. Once it is finished baking remove it from the oven and let it cool completely.
Spread nutella. When cooled and ready for the “sauce” place 1 cup of Nutella in a microwave-safe bowl and microwave for 15 -30 seconds until it is slightly runny. Spread over the brownie layer leaving a 1-inch edge around the outside of the brownie. Sprinkle on the Halloween candy.