Grease a 15-inch pizza pan. Prepare the brownie mix according to box directions. Pour into the prepared pan. Bake for 20 minutes, or until done. Remove from the oven and cool. Beat the cream cheese, pineapple, and sugar together in a bowl. Use any reserved pineapple juice at this time, if needed, to soften the mixture to a good spreading consistency. Otherwise dispose of or save the juice for another use. Spread the mixture over the cooled brownie crust. Arrange the banana and strawberry slices over the cream cheese mixture. Sprinkle with the chopped nuts and drizzle with chocolate ice cream topping. Refrigerate. To serve, slice as you would a pizza, and enjoy!