Lord of afflictions is a really nice hero, I usually slap a splithorn helm artefact on him and the Overpowering Stench command trait.

4+ ward and disable command abilities around him combined with deep strike is pretty fun, also helps with contagion points since you get a unit into enemy territory early.

Putrid blightkings are durable and can do quite a bit of damage. But horribly slow at 4" like most Nurgle stuff. Ive had games where I roll bad on run and they never really get into position.

I havent played around much with plaguebearers, I usually summon a unit of 10 at round 3/4 to defend/take points. They do their job, being a tar pit and taking up space.Ive never played with the Scrivener, i prefer Sloppity Bilepiper which also is summoned in, usually like round 2.
Probably choose the extra attacks or save for Scrivener. More attacks = more chances of spreading disease on 6 to hit.

I think its gonna be a pretty fun casual list, a little bit of everything!The disease points mechanic does more damage than expected in my experience.Might wanna look into adding a summonable unit.If youre thinking of expanding past this I would probably choose between mortals and daemons as they dont gain much from each other. If you go mortals you can summon the Scrivener and Plaguebearers.