Preheat the oven to 180C / 350F and line a baking tray with baking parchment.
Roast the hazelnuts: Spread the hazelnuts on the baking tray and bake for 15-17 minutes.
Place the hazelnuts in a sealed Ziploc bag and crush them with the rolling pin until they are small chunks.
In a mixing bowl, cream butter, granulated sugar and brown sugar together until fluffy.
Mix in the egg and vanilla extract until combined.
Now, mix in flour, salt and baking soda.
Stir in hazelnuts and chocolate chips until the dough comes together. Chill the dough for 30 minutes or so (optional).
Scoop about 1 tablespoons of the dough and roll them into balls and then put them on the prepared baking tray, leaving space between the cookies to spread.
Bake for 10 minutes, then remove from the oven and place on a wire cooling rack to cool.
Notes
Try to make all your cookies the same size. This ensures they bake evenly. I used a cookie scoop for this purpose.