Preheat the oven to 325°F (165°C). Line two baking sheets with parchment paper.
In a medium bowl, whisk together the all-purpose flour, baking soda, and salt. Set aside.
In a large bowl, mix the melted butter, brown sugar, and granulated sugar until well combined and smooth.
Add the vanilla extract, egg, and egg yolk to the butter and sugar mixture. Beat until light and creamy.
Gradually add the dry ingredients to the wet ingredients, mixing until just combined. Do not overmix.
Fold in the cocoa nibs evenly throughout the dough.
Using a tablespoon or cookie scoop, drop dough onto the prepared baking sheets about 2 inches apart.
Bake for 12 minutes or until the edges are lightly golden but the centers are still soft.
Remove from the oven and let the cookies cool on the baking sheets for 5 minutes before transferring them to a wire rack to cool completely.