Its pretty rough on Noctus when more than one appears. Even with a load of tanks because he has a lot of armor on his front.
So what I usually do is get into a Mantis, because it’s quick and tough with wheelman. I then get behind the Warden, but far enough away that he doesn’t use melee. You can do this with a tank or even on foot but I think the Mantis is the best for protection, speed and manuevrability.
The Warden then starts hitting you with EMP so you shouldn’t be doing much but can take a lot of fire. However, this means your four guys with Scorpians can hit his exposed back and do massive damage to him. Plus you also stop Warden putting EMP on said tanks.
Also, just as an aside. The Plasma Caster is amazing at killing knight and hunter bosses. Just fully charge each shot and you can do obscene amounts of damage to most of those bosses.