Well, **Chirrut** thought he was!
He said something like "the Force reveals a darkness around someone who's about to kill". So however he sensed it, HE thought it was through the Force.
I didn't mean to suggest that Chirrut was delusional or fooling himself. There seems to be a disconnect between the advance promotional material and the dialogue of the film re: Chirrut.
Everything I read ahead of time gave me (what I thought was) a pretty clear impression that there were no Jedi - more specifically, no Force-users in this film (except Vader, of course). That all these characters were (for lack of a better phrase) "ordinary folk", and we were seeing the war through that non-Force-user lens. And unless the Databank is playing cagey with their wording, when they say Chirrut "has no Force abilities" - period - then I am left thinking that he's not Force-sensitive, but rather a fervent devotee of the Force.
But then his quote from Eadu seems to contradict that.
So I see four possibilities:
1.) He is Force-sensitive, with the ability to sense the Force but just cannot
use it. If so, odd that the databank would leave that latter part out.
2.) He is FS and
could have used the Force, but was never picked up by the Jedi as a child and trained.
3.) He is FS and
does use the Force through his fighting skills.
4.) He is
not FS, and just a fervent Force devotee who also happened to hone his other senses (without a Force-assist) to compensate for his blindness,
á la the martial art movie archetype. And maybe he can't sense the Force directly, but has learned to pick up cues from his environment when the Force is or has been "in action" nearby. Like, he can sense everything interacting with the Force, like water reacts when a ship moves through it. Even though Chirrut can't see the ship, he can tell its size, length, speed, etc. by the wake it leaves in the water.
I am cool with any of the above, but I am guessing that the canon answer is #4.