I had in mind to spawn Nexus in Hyperspace, instead of regular systems. But alas, I dunno how. So for now they're stuck in Corvus.
You can capture their ships, because I doubt there's a way to disable that. Even if there was a way to disable capturing for this faction, then I wouldn't know how to implement it, due to probably involving heavy scripting.
But chances are probably really low to get your hands on one, seeing how I rarely get the chance to capture a vanilla ship.
If you have a strong capital ship, go for the main ship as quickly as possible. If the main ship is destroyed, its drones will be destroyed as well.
Thanks for liking it!
Maybe I'll make them their own system, like people suggested. I already got an idea and it sounds like fun.