If we knew some 'magical' way to remove incubi, I would be damned if we did not assisted with this project straight away. General rule is that we can extract it with use of advanced surgery within one hour without permament damage.
In this case we need more details to make a judgement. Dependable on level of control this 'infiltrator' possess on host, it will kill itself together with subject in case all other means of escape are exhausted to prevent capture. More advanced stage and extent of infestation, more complicated it gets. If it's not what we could name 'larva' you will require assistance of psionics which received that gift from Nomads that way or another. As most of them would reside at Malta for obvious reasons and have strong ties to Slomon K'Hara, it will be difficult if not impossible to enlist their help.
Effects of such operation may range from permanent brain and nervous damage through disfunctional crucial organs to total paralyze or simply death due to all implications. Not to mention already suffered mental trauma, with way more of it to come. Even if you managed to knock Nomad out it may not be enough to stop physical pain, if he still struggles to stay one of us. Finally, do not rely any kind of info to subject (and incubi in the process) as it may leak to rest of them.
100% succesful rate treatment is ultimately old-school bullet in the head.