Preheat oven to 400°. Bring water and butter to a boil, remove from heat and whisk in flour. Transfer to a plastic or glass bowl and using a hand mixer, mix in eggs one at a time. Spread evenly on a large greased cookie sheet or jellyroll pan. Bake at 400° for 15-20 minutes until light golden brown. Let cool completely before topping.
In a mixing bowl, add the milk to the pudding mix and mix thoroughly. In a separate bowl, beat the cream cheese until it becomes fluffy. Gradually add the pudding mixture slowly as you continually beat the mixture. Spread pudding mixture on the completely cooled crust and then immediately top with cool whip.
Heat the Nutella and milk in a small saucepan over low heat. Stir until melted and heated through. Remove from heat and drizzle sauce over the top of the cool whip.