Nurglings and Beasts of Nurgle often serve little tactical purpose. I gave my Beasts a run at the end of 9th Edition even spending considerable time rebasing them and improving the paint jobs. The Nurglings finally got a go in tenth Edition Warhammer 40,000 and they underwhelmed but I'm not ready to give up as I think having a sea of Nurglings on the battlefield just looks and sounds cool and I'll spend considerable effort tying to make it work. I previously proposed the following Nurgling Tactics. I always wanted to try out an army with a lot of Nurglings, finally in 10th Edition I will realize my dream.
I call my Nurglings George Jrs because I call my Great Unclean One "George". George Foreman has multiple sons named George Jr. My GUO is like George Foreman thus my Nurglings are the George Jrs.
I spent entirely too much time painting these models. Most people just dry brush them. I highlighted every single gobulat of puss. Each stand is painted differently. I used a mix of old style "humorous" and the then new style "mean" Nurgling. I prefer the old style, I generally prefer the old anything when it comes to GW. I'd almost forgotten I gave every Nurgling beady yellow eyes. Now many years later I've painted even more slowly and carefully.
Although not a Troop choice, you can still field them in 40K as allies or Spawn, though they have a different base size to Chaos Spawn. Although they look cool especially after getting rebased and refresh for 9th Edtion, their combat ineffective especially for their point costs is often not overwhelming. The old models are a pain to assemble and their best use in the game was to take a lascannon for the team. There is something about a wall of daemon flesh between you and the enemy, but alas Nurgle daemons are generally too slow.
I have a green one called Sluggie, a brown one called Slimey, and a purple one called Esmeralda. Esmeralda's a girl.