Cocoa nibs are the raw form of chocolate with nothing added or processed. The inner part of the cacao bean, nibs are cured and roasted after gathering to bring out the full chocolate flavor.
You can use these cacao nibs like you would a dry hop, by adding the cacao nibs to your secondary fermenter or keg for a couple of weeks (4 ounces per 5 gallons is a great place to start), allowing the beer to draw out the subtle flavors and aromas of the cacao nibs. They can also be used in the boil or mash - wherever you would like to experiment with them. Adding the nibs pre-boil will impart some bitterness, so use a lot less than you would when adding them to a keg.