Maybe some companies are having trouble unpacking it and that is why they are detecting it.
To be honest,I've seen a few legitimate software,
(not really much,exceptions to the rule I'd say),
packed with later commercial versions of NSPack 3.xx...
but with this version/variant and the older 2xx series,well,I seriously doubt...
Maybe things are different over there in China,don't know,lol...
but for me,this is one of the few times,
that I will certainly won't blame AV companies for detecting it,he-he...

...haven't had the time yet to check this NsAnti packer more thoroughly,
thereby I'm not sure yet if the executable itself is actually "clean":
the samples are always detected as "Packed.Win32.NsAnti.blah-blah...",
but VirusTotal reports all kinds of weird results regarding the packer himself,
so I couldn't figure out by the report a logical explanation...
It is also supposed to be a "cracked" version,
and this obviously raises the suspicions' bar a bit higher.
But exactly because I got really curious with VT's results,
I've checked hashes with every different NsAnti copy I've found on the net:
and they all matched...all sites,and also a couple of rce forums I checked,
they all host exactly the same release...

A really quick look reveals that an ep_true sig is not possible,
it's behavior is quite similar with the one that early 2.xx NsPack versions exhibit,
this doesn't happen with v3.xx and afterwards...
It should be equally difficult/easy to unpack it though,
as I noticed there's way too many repeative patterns/instructions...
...I have a somehow similar chinese thing here in my packers' archive,
not that much known to the (western world) public,called Anti007...
far more recent though than this NsAnti,a couple of different versions of it...
Hadn't bothered more than a few minutes with it,
but it had also given me the impression that it was NsPack-based...
maybe I was wrong on this,don't think so though,
I'll have to look at it also at some moment,now it makes me wonder...

NsPack seems to somehow have a whole "school" of variations/mods,
say like Morphine,or yoda's sources...what puzzles me though,
is that in contrast,at least from what I am aware,
NsPack's src wasn't ever released to the public...