Never been a huge fan of Chaos spawn models and he price they go for! So solution is some undead ghouls to tick a similar box, I probably wouldn’t run all 3 at the same time but they do allow for a cheap way to fill in the fast attack slot for a Battalion.
https://www.flickr.com/photos/docbungle/37837653441/in/album-72157687899079483/
The Wargaming Bear 
I use the same thing. They’re a perfect counts-as Spawn.
I often run a squad of 5 of them, and in 8th they tear stuff up. I thought they were great in 7th, but they went from great to awesome in 8th.
I have yet to use them, currently the idea is for them to be cheap drops to get me to a battalion 🙂 but they do look like great dostraction pieces
They can potentially take on anything in combat. After a few games you may come to love them.