Not really been any mention of chaos orks for a long time but, and the fluff meisters can help me out here, it's not actually outside of the realm of possibility.
I remember it saying that the inexorable spread of corruption was not a threat to Ork Kulture as it is to the Imperium but there are still individual warbands linked to chaos.
If it's going to widespread anywhere it would be near the eye of terror, and for the forces of the warp there's a certain charm to be found in the orks. They are basically more chaotic that any of your regular human worshippers and individual gods would find they have things very much in common with them.
They share Papa Nurgles love of green, stinking filth and are basically a fungal infection on the face of the Galaxy.
For Khorne they are savage and blood thirsty as most of his followers AND attack in hordes with scant regard for their own safety which can only be good for a Blood God.
Even Slaneesh, whose followers are usually filthy pervs, must appreciate their sense of humor when it comes to hurting other things for fun and some of their insane lust to go fast.
The benefit of chaos orks for DH games is that it gives you a surprise way to connect ordo's together, to introduce Inquisitiors or acolytes from other ordo's to get in the way or just a way for Malleus / Heriticus acolytes to ligitimately go after some orkses.