Preheat oven to 350 degrees F. Spray two 6 count muffin top pans with non stick cooking spray. Set aside.
In a medium bowl, whisk together flour, baking soda and salt. Set aside. In the bowl of a stand mixer, cream butter and sugars until creamy and smooth, about 3 minutes. Add egg and vanilla extract, beating until combined.
Slowly add dry ingredients to wet ingredients and mix until just combined. Stir in the chocolate chips.
Press a thin layer of cookie dough in the bottom of each muffin top cup. Add a tablespoon of Nutella into the center of each cookie. Cover each cookie with remaining cookie dough by carefully pressing the cookie dough over the Nutella. Make sure the Nutella is covered. Sprinkle cookies with sea salt.
Bake cookies for about 14 minutes or until browned around the edges, but still soft in the center. Let cookies cool for 10 minutes in the pan before transferring to cooling rack.
Note-if you don't have a muffin top pan, just make extra large cookies. Take a scoop of dough and flatten in the palm of your hand. Add a spoonful of Nutella into the center. Top with more dough and carefully roll into a large cookie dough ball. Place on a large baking sheet lined with a Silpat baking mat or parchment paper. Sprinkle with sea salt and bake.