Preheat oven to 325. Using an electric mixer, combine flour, cocoa, sugar, baking soda, salt and instant coffee. Using the paddle on low speed, add nuts and chocolate chips. Lightly whisk eggs and vanilla and add to flour mix at low speed, just until dough comes together. Turn out dough on lightly floured surface and knead lightly to incorporate any unmixed dry ingredients into dough. The dough will be very sticky and I would suggest either flouring or wetting your hands to form into 4 logs, each 2 inches in diameter. Place on parchment lined cookie sheets and bake for 30-35 minutes. The logs should be firm to the touch with cracks on the surface. Reduce oven temp to 300 while logs are cooling slightly (about 10 minutes). Cut logs on slight diagonal into 3/4 inch slices. Lay cookies, cut side down, on cookie sheets and bake additional 20 minutes, turning over half way through. Cool completely on racks.