Board Thread:Metal Gear Solid V/@comment-5085906-20140619165117/@comment-6747658-20140624123415

Indeed, I also highly doubt that he is related to Chico/Amanda in any way, it would be too far of a stretch really.

But all in all, IMO, it is safe to conclude that Chico is not Quiet, no mater how many people will still find excuses to claim this.