In a large mixing bowl, cream together butter and sugar until light and fluffy with a hand mixer. Add the eggs one at a time and mix to incorporate. Add vanilla and mix thoroughly.
In a medium mixing bowl, combine all-purpose flour, baking soda, kosher salt and cocoa powder. Use a whisk to fully mix the ingredients and remove any clumps.
Add flour and cocoa mix to the creamed butter and sugar. Mix together until dough appears completely combined. Add walnuts and chocolate chips and stir them into the dough. Drop by large teaspoonfuls onto an ungreased cookie sheet. Or roll into balls, place about two inches apart on the sheet, and flatten slightly with your fingers.
Bake for 9 minutes. The cookies will appear to be just barely firm with a sheen to their surfaces. Allow to cool on the sheet for about one minute before removing to a cooling rack to cool completely. Store in airtight containers.