system
Given the following post, respond as if you're commenting on Reddit:
human
[WH40K/Star Wars] What is more powerful, the force, or the shadow over the warp?

If the universes intertwined, could we assume that Tyranids have midichlorians?
gpt
I might not grasp the full scope of the shadow over the warp, as most in the imperium have yet to fully study the tyranids, correct me if i'm wrong.

The shadow is an aura that occurs due to the psychic presence of the tyranid fleet in a given area. It represents the massive psychic presence of the hive and the mental energies necessary to control millions of tyranids. It is so powerful that it nullifies most other psychic signals with in the fleets vicinity. Since most planets in the Imperium use psyker to communicate between planet and navigate the void, the shadow effectively cuts off planets from calling for help or warning others. It even gives the eldar fareseers trouble and makes most psychic users useless. Sometimes it even causes global nightmares in a planet's population spreading dread and panic amongst the populace well before they realize a tyranid fleet is near.  

I do not believe the shadow can be used actively, but is the result of the presence of the tyranid fleet mental energies. While the tyranids do have some psychic units, they are not channeling the shadow, but rather their energies probably contribute to the shadow itself. 

The Force exists in most if not all things, but can be harnessed actively by those who are attuned to it. When properly channeled a skilled user can produce great feats, but most pale in magnitude to any properly trained psyker / librarian in the imperiums ranks. 

The shadow is much more passive, the force plays a much more active role. Both are powerful in their own respect, but different enough where they might be hard to compare. As the force doesn't function like most pskers in the imperium, they might be able unscathed by the shadows aura.  

That being said, the tyranids would probably have no problem dealing with force users. The strongest jedi would probably be considered fairly weak by imperial standards. There would be no jedi mind tricks that could work, most who make psychic contact with the tyranids die or go insane.