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Alright my friend and I have a team tourny coming up and he has to use chaos and I can use several different armies. Right now were thinking tau and chaos and I have posted the list below. Let me know if that sounds like a solid set of lists or not. If not what would be better army comp or army type with chaos. It is a shared force org by the way.
7 nurgle marines
(Shasel joins here)
2x6 fire warriors
(reserve/ hide and capture home objectives)
2 hammer heads
I would say the only change I would make is maybe to the chaos actually. Lash w/ MoS on the prince would be horrible to play against. If something gets too close to your tau they could pull it back. Id maybe question the plagues since you have the shooting covered, but they are still super awesome, so its not bad to keep them in.
But yes, chaos and tau complement eachother really really well.
We didnt go with lash due to the new inconsistancy with the new having to hit faq. We had 10 points left over so we went with tzentch for some added surviveabilty on the prince. Do you think more bezerkers over plags. I figured the extra melta would be nice and they are tough as balls at holding objectives.
Id say its a matter of choice on the plagues vs more berserkers. Its not a bad idea to have something that can walk up to a spot midfield and not die a fast and violent death.