Gorebeast Chariot

Now, I've personally used them only a couple of times and in two quite different ways:
I started out using one as a slow flanker in combination with a small unit of Forsaken.
This didn't prove particularly effective as the slowness of the chariot in combination with the speed of the Forsaken resulted in the former lagging way behind while the latter was baited away to pursue some juicy target.

The other way I've used the unit is by having two of them take the roll of a center-placed battering ram. This has proven far more succesful the miniscule amount of times I've not succumbed to my easily baited nature and had each of them chase after their own target. The downside to having them positioned in the middle is that it limits my army to a slow crawl if I want to maintain some kind of battleline.

Besides these two ways of using them I've lately started considering having a pair of Gorebeasts Chariots positioned to guard the non-offensive flank in an Oblique Order battle-plan. The slowness of the unit would allow for the pair to naturally fall behind the rest of the army while they simultaneously create a wide threat area for anything that tries to exploit the relatively weaker flank or for that matter whatever center placed unit within reach. The threat of being simultaneously charged by two Gorebeast chariots should be enough to scare away most threats from that flank and if the Oblique Order-plan fail I'd still have a very strong flank left to use when it eventually gets to the combat zone.

I have tried running two Nurgle ones a couple of times. I love them but still, need more tries before I can give good feedback.

I remember even running mine into an HPA in two separate turns and they held up even against that.

Eventually they died but the HPA had full flank on me and I was surprised how long they hold.