Lightly grease three or four baking sheets or line the baking sheets with silicone mats.
In a large bowl, whisk together the sugar, salt, espresso powder and cocoa. Set aside.
In a separate bowl, whisk together the egg whites and vanilla extract.
Add the egg mixture to the sugar mixture then stir to combine. Be sure to scrape the sides of the bowl.
Add the nuts and chocolate chips then stir to combine. The batter will be sticky and thick.
Drop the batter by rounded teaspoons onto the prepared baking sheets.
Preheat the oven to 350F. Allow the cookie batter to rest on the baking sheets while the oven preheats.
Once the oven is preheated, bake the cookies for 5-7 minutes. The cookies will slightly spread and be a little shiny when they are done.
Remove the cookies from the oven and allow them to cool on the baking sheets.
When the cookies are completely cool, use a spatula to carefully loosen them from the pan.