Cacao nibs are crushed and roasted seeds from the Cacao plant. It is these seeds that are the key ingredient in chocolate. While not technically chocolate themselves, our nibs do have a wonderful cocoa smell to them, and will provide a very subdued cocoa-like flavor to any beer.
Suggested usage is similar to dry-hopping, add the nibs in your secondary or keg. 4 oz of nibs per 5 gallons is a good starting point. Nibs can also be used in the boil (they will impart some bitterness), in the whirlpool, or made into an alcohol tincture and added to the beer.