I think this is a somewhat difficult subject.
In my case I was sick, the Doctors were in their words extremely “pessimistic” of a complete recovery, if there was to be a recovery at all.
Yet Rav Shteinmann said all would be well (along with other Gedolei Yisroel).
I did merit a complete recovery and the Doctors called my case “humbling”.
Does that qualify as a Nes?
I do not know, and my emunah is not dependent on it.
the thing I do take from it is that they is HKBH and while Doctors have a Heter of Rapoh Y’Rapeh they do not have the power of predictions.