What about Pestigors?
The current Rotbringer list has only one unit.
If Nurgle get the Tzeentch, Bloodbound treatment, it makes sense to add
pestigors, acolytes, beasts and something to deal with shooters.
The current Nurgle army is slow, predicteable, low fire powered, low Rend.
As of now Nurgle has very few options when it comes to surviving the shooting armies such as Stormcast.
A battletome will be a great help but It is really far from enough.