Skink + Kroxigor units have done wonders for me against the Warriors of Chaos. It is really easy to get a flank on them, and one of the less obvious Lore of Metal spells turns their weapons into lead. I had a unit of 11 skinks + kroxigor side into these guys, Krox took out 2, remaining guy took out two skinks (got real lucky he did) I had 2 ranks, a flank, and outnumber on him. He then needed 4's to hold (chaos leadership isn't super amazing) and bolted, and got run down.
One Kroxigor can kill one knight without too much luck, and allow no retatliation if they have a flank, 2 ranks, kill, flank, outnumber puts you at winning by 5. (leadership 3)
Warriors of chaos have the problem that unless they take liberal numbers of marauders (which they often don't for some reason) then they are not going to be able to easily hold a flank against all the speedy bullcrap in your army. Any good hammer unit can hit knights in the flank (or even the front for ancient stegs) and have a good chance of breaking them. The warrior blocks themselves are twice as likely to succumb to skink pews, and sallies and even razordons do all-right against them.
The problem with Chaos is that their heroes are often unstoppable serial rapists that can not be defeated by any reasonable means. I have lost a game trying to save toad from a lord on a dragon by throwing everything at him, and had only two heroes remain, defeating the rest of my army when he had been tabled except them since turn 4 or 5. Frankly, I say just avoid them and count your losses, get table quarters, get banners, and you can get a win.