>>95836690
>How the FUCK do you beat them?

Orks'll get um'.

I don't have a citation for this, so I don't know if I made it the fuck up or it's from the earlier versions of Warhammer that let you field plastic dinosaur toys: Orks counter Tyranids.
What specifically happens is Tyranids can't perfectly convert Ork biomass into Tyranid biomatter; there's supposedly a diminishing return with the Tyranids where the more Orkish biomass they consume - the more they're made out of Orkish biomass. To the point where they stop being Tyranids. Orks aren't just Orks, Orks have an entire symbiotic fungal biosphere attached to them and a mild hivemind that eventually bioaccumulates and completely astroturfs the Tyranid swarm and supplants their own psionic presence over it.
Granted, it's a war of attrition; the Tyranids can beat the Orks if they nip them in the bid as quickly as possible, but the general idea is any kind of protracted conflict with the Orks will gradually end in defeat for the Tyranids- and more Orks.