Have ingredients at room temperature. Line a large cookie sheet with parchment paper; set aside.
In a medium bowl, combine and whisk together the flour, cocoa, baking powder, baking soda and salt. Add in the finely chopped nuts and chocolate chips; mix together to combine.
In a large mixing bowl, add the eggs, softened butter, and vanilla extract. Beat mixture until smooth and creamy, about 2 minutes.
Stir the flour mixture into the cream mixture; mixing until combined. Divide dough in half.
Lay the dough on a slightly floured surface. With floured hands, shape dough into a log that will fit on your cookie sheet....10x2 or 13x2.5. Measurements doesn't have to be exact. Transfer the log onto the prepared baking sheet and shape it up a bit more. Repeat with other half of dough. Set logs 2-3 inches apart on the baking sheet.
Bake for 25 minutes. Remove the cookie sheet from the oven and cool it on a wire rack for 10 minutes. Reduce oven heat to 275 degrees.
Gently move one log at a time onto a cutting board. With an electric knife, cut each log into 3/4 inch slices diagonally. Place slices back onto the parchment lined cookie sheet.
Bake the sliced biscotti at 275 degrees for 10 minutes, turn them over and bake for another 10 minutes.
Remove biscotti from cookie sheet to a wire rack and cool completely until hard and crispy.