In normal case, as Tyranids are, in general, broken beyond any reasoning, winning wouldn't be a problem
However, tournament rules forbid you from taking evolutions and limit your launch bays. Two of your fleet important strengths.
However, what I can say: You need those 8 launch bays you are allowed to take. With Tyranid double limit, it's still more ordnance than anyone except maybe Tau can field. And Tyranids have pretty terrible ordnance, so they need lot of it.
Second of all - enemy has their long range lances and nova cannons limited. That makes getting close to them a bit easier. You want to be close to them most of the time.
Krakens are crazy tough for their cost and in small points are really hard to shift. It really depends on what weapons you like, but In my experience, pyro-acid is great - huge squadron on lock-on devastated everything it can reach.
Alternatively, claws. With enough Kraken latching onto a ship, it will go down in spectacular fashion.
Also, bioplasma escort drones - they're slow, but first, you're required to take some, second - keep them close to the carrier hive ship and make sure no one will ever come close to it.
Everything here is, of course, my oppinion. Tyranids are a strong fleet and have many viable ways of winning the game.
