Spread the 2 fl oz of Nutella evenly across the bottom of the graham cracker crust using an offset spatula or the back of a spoon. This creates a rich chocolate-hazelnut foundation that prevents the crust from becoming soggy while adding intense flavor in every bite. Work gently to avoid breaking the crust.
In a medium bowl, combine the 12 fl oz of melted Nutella with the softened cream cheese, sea salt, and vanilla extract. Stir vigorously until completely smooth and well combined—this ensures the cream cheese doesn't clump and creates an evenly textured filling. I find that warming the cream cheese to true room temperature (not just cool from the fridge) makes this step much easier and prevents lumps from forming.
Gently fold the whipped topping into the Nutella-cream cheese mixture from Step 2 using a spatula, working in 2-3 additions to maintain airiness. Use a folding motion—cutting down the center, sweeping along the bottom, and turning the bowl slightly—rather than stirring, which would deflate the whipped topping and result in a denser pie. Pour the filling into the crust over the base layer from Step 1 and smooth the top gently.
Refrigerate the pie for at least 4 hours, preferably overnight, until the filling is completely firm and set. This time allows the flavors to meld and the texture to become creamy rather than mousse-like. I recommend chilling overnight when possible—the pie tastes even better the next day as the Nutella flavor deepens and becomes more integrated throughout the filling.