Well, the results are in and it's pleasing to the Hive Mind: A Victorious slaughter for the Tyranids!
He played Tau with a commander and bodyguards, two fire warriors squads of twelve each, a hammerhead, some sniper drones and gun drones.
My list looked like this:
1000(998) pts
HQ – Hive Tyrant 143 pts
(Winged, Toxin Sacs, Scything Talons x2)
Troops – Genestealer Brood 128 pts
X8
Troops – Genestealer Brood 128 pts
X8
Troops – Hormagaunt Brood 160 pts
X16
Troops – Termagant Brood 96 pts
X16
Heavy Support – Carnifex 148 pts
(Enhenced Senses, Barbered Strangler, Venom Cannon)
Heavy Support – Zoanthropes 195 pts
X3(Warp Blast, Synapse Creature)
I may not remember everything correctly but it played out something like this:
I got the first turn and actually managed to get a first turn assault with my hormagaunts! Only target I could reach, though, was the sniper drones. I do something stupid and split my army up in two and attacking from two flanks - hormagaunts, genestelaers and tyrant on one flank, the rest on the other. My zoanthropes spread out between the two flanks. I kill a pair of gun drones with my hormagaunts but that's it. Miss my shooting. The Tyrant doesn't quite get within assault range and is left out in the open (second big mistake). During his turn he blast my tyrant with gun drones, suits and the hammerhead. Luckily the tyrant is still standing, but with only one wound left. Some fire warriors finnish the job though and at this point I think "I'm beslubbered". The hormagaunts finnish of the sniper drones. Next turn though genestealers move up towards the suits (behind cover), a zoanthrope move up to bring synapse to the hormas and the hormagaunts move towards the suits too. The other flank keep marching toward the fire warriors and hammerhead. My carnifex almost annihilates a squad of fire warriors and they're pinned (not sure which round this happened but what the hell). My termies move up to screen my other group of 'stealers sneaking around in some ruins toward the other fire warrior squad. The zoanthropes start blasting the fire warriors two but to no avail. Back to the suits - they're in deep amphetamine parrot when they're assaulted by two full broods - genestelars and hormagaunts. They're killed pretty fast. He kills some termagants in his turn. Next turn I kill the gun drones and stun the hammerhead. the termagants move closer and starts shooting the remaining fire warriors but without kiling anything. I can't really remember what happens next in great detail but eventually he's left with a squad of fire warriors, an immobilised hammerhead without it's railgun. His forces is surrounded by my genestealers, gaunts, zoanthropes and carnifex and is killed before the end of the fifth turn. All in all I wiped out his enture force and controls three table quarters. He kills half of my termagants, a couple of genestealers, hormas and my tyrant.