Adding flavours at bottling

I have a 5g batch of porter I am looking to bottle next weekend.

I am planning on splitting the batch and bottling 2.5g with cold brew coffee (aiming for 8oz in 2.5g).

Was just thinking about adding some cacao nibs to this idea.  However - from what I can tell the chocolate flavour comes from oils in the cacao nibs - so cold brewing them with the ground coffee will do virtually nothing I assume.

What if I sterilize the water for the cold brew by boiling it then boiling for 5 mins with the cacoa nibs in it.  Cool it and then cold brew with the cacoa infusion?

Or will the oils turn bitter after bottling?

Anyone tried this?  Should I split my 5 gallons 3 ways and bottle 1/3 normal, 1/3 coffee, 1/3 coffee and cacao?