Preheat the oven to 350 F and line 3 cookie sheets with parchment paper. In a bowl, whisk together flour, salt, and baking soda.
In a mixing bowl, beat the butter and both sugars using an electric mixer until combined and fluffy. Add the eggs, one at a time, beating well after each addition. Beat in the vanilla.
Turn the mixer into low speed and slowly add the flour mixture. Mix until just incorporated. Mix in the chocolate chips.
Scoop out a heaping tablespoon of dough, forming it into a ball in your hand. Use your palms to flatten the dough. Spoon about a teaspoon of Nutella in the center and fold the edges of the dough to cover the Nutella. Pinch the edges together to seal the ball close.
Repeat the process with the remaining cookie dough. Arrange the balls on the prepared baking sheets, spacing them evenly apart. Bake for 10-12 minutes or until golden brown.
Instead of measuring out the Nutella, just chill the whole jar in the fridge and scoop out from the jar itself when filling the cookies. You won't need the entire jar.
It is important that the Nutella is chilled for a few hours in the fridge so that it is nice and firm when filling the cookies, instead of runny and messy.
The cookies are done when they have turned golden. They will still be soft to the touch and will continue to firm up to perfection upon cooling.