I have a founders breakfast stout in the secondary. recipe calls for adding an additional 2 oz of cold brewed coffee at bottling, 2.5 oz bakers chocolate powder at 15 minutes, and 1.5 at the 15 min also. Not really sure why the powder and nibs are thrown in at the same time, but that is what the recipe says.
I am thinking that I would steep the nibs for a few weeks and then add them to the secondary after its been racked. I believe this would add to a stronger chocolate flavor with the final product. As a former mead maker adding to the secondary always brings out more of the flavor your adding.
As a word of caution though. Nibs tend to expand so, steeping them in gin, vodka, or ever-clear is not a bad idea. Not sure I would just throw them into the secondary.
I will see what happens with this patch and adjust according to taste.