My knowledge of nid/chaos fluff is a bit rusty, so bear with me on this.
The Tyranids have a large warp presence that disrupts warp communications/travel as they get close by.
Chaos, by it's very nature is a wapr-based thing.
So what happens when the two encounter each other? Do the Nids have an advantage, disrupting the warp/Daemons etc, or is Chaos strong enough in the warp to cope, or even overpower the Tyranids warp presence/disruption?
Was just thinking about this recently. Any help or clarification would be great .