Once the nomad city got done imploded, it sucked away half the nomad primary fleet see? So whatever nomad ships were left probably did cloak and buggered off to Iota. The rest of the "Nomad" forces were probably the remains of the infected Rheinland fleet that got done excommunicated from the rest of the nomads cos they were as good as dead see?.
As for the sun exploder, killer, doodad, dynamo....thing. How do you know there's more than one? How would we know if the one that blew up the sol was destroyed with the blast? Was it designed that way? Were they different nomads altogether? Am I asking too many questions?
It's all very skeptical amongst the community. At least until three people invent the nomad lore and everyone sheeps along. But I suppose you've got to give it some credit, they did a pretty alright job.