Preheat your oven to 350°F. Line a baking sheet with parchment paper or a silicone baking mat.
In a medium bowl, whisk together the flour, baking powder, and salt until well combined. Set aside.
In a large mixing bowl, cream together the softened butter and granulated sugar until light and fluffy, about 2-3 minutes.
Add the eggs, one at a time, beating well after each addition. Then, mix in the vanilla extract until incorporated.
Gradually add the dry ingredients to the wet ingredients, mixing until a dough forms. Fold in the chocolate chips and chopped nuts, if using, until evenly distributed throughout the dough.
Divide the dough in half. On the prepared baking sheet, shape each half into a log about 12 inches long and 2 inches wide, spacing them a few inches apart as they will spread during baking.
Bake in the preheated oven for 25-30 minutes, or until the logs are lightly golden and firm to the touch. Remove from the oven and let cool for 10 minutes.
Using a sharp knife, carefully slice each log diagonally into 1/2-inch thick slices. Place the slices cut side down back onto the baking sheet.
Lower the oven temperature to 325°F. Bake the biscotti for an additional 10-15 minutes, flipping them halfway through, until they are golden brown and crispy.
Remove from the oven and transfer the biscotti to a wire rack to cool completely. Once cooled, store them in an airtight container at room temperature for up to two weeks.