Beat the butter in a large mixing bowl with an electric mixer on mediun to high speed for 30 seconds; add sugar, coffee crystals, baking powder, cinnamon, and 1/8 teaspoon salt; beat until combined.
Beat in eggs until combined; beat in cocoa powder and as much of the flour as you can with the mixer; stir in remaining flour with a wooden spoon; stir in nuts.
Divide the dough in half; shape into loafs, using flour on hands; Place loaves on greased cookie sheet about 5 inches apart on cookie sheet; flatten to 3-inches wide; Bake for 20 to 25 minutes or until firm and a toothpick insterted in center comes out clean; reduce oven temperature to 325 degrees.
Cool on cookie sheet; transfer loaves to cutting board, cut each loaf diagonally into 1/2-inch-thick slices; Lay sliced, cut side down,on cookie sheet; bake for 8-minutes; turn slices over and bake 7 to 12 minutes more or until dry and crisp; transfer to racks and cool.
For espresso drizzle, in a medium bowl dissolve instant espresso in 1 tablespoon water; stir in powdered sugar; add additional water, IF necessary, to make drizzling consistency, drizzle over biscotti's.