Am I right in thinking that you routed the Nomad's Rohloff cables on the right side of the head tube? I've got them on the left side where they rub the paint off.
Dan has it right, one either side. The Nomad's guides are positioned different to the Mercury, directly underneath rather than off to one side. So one cable each side on the H/tube gives an even curve, not that it matters for anything other than aesthetics. On the Merc, they're the same side of the H/tube as the guides.
Whatever you do it's going to rub paint off if you don't protect it, proper 3M Helicopter Tape (Not the stuff claiming to be such that's all over eBay) disappears into the paintwork and is hard to spot even when you know it's there.
There's also some Jagwire rubber sleeves which I think slow the effects of rubbing rather than eliminate it, but I had them anyway! You can see one of those on the Ti bike where I obviously have no paint to worry about, it does stop the cable clattering against the H/tube on rough ground. I have them on the Mercury underneath the downtube for the same reason.
I don't know if it's those or the heat shrink on the brake hose that eagle-eyed Dan spotted, the latter is waiting for the rear dynamo cable when I fit the lights, which will be when I cut the steerer (Or when the evenings get dark, whichever comes sooner)