According to the latest rumors, there is an Age of Sigmar campaign coming in the new year that will involve the Chaos Warbands. When things get a little closer I am sure that we will see more info on it.
Please remember that these are vague rumors. We have had a rumor or two from this source before. I am assuming that this is not that far out.
via Mad Mek on Faeit 212
next year theyre running a campaign in AOS , and its Chaos warbands based