I'm not sure which specific Nanoha series this is supposed to be from. I know it's not from the first series but that's about it.

Probably the movie then. Chibi Fate only shows up in the movie and the first two seasons, and there's nothing I can see here that would give this an A's timestamp (Can't see whether Bardiche has the cartridge system installed for instance).

I'd say it's movie Fate.
My main reasons are
- The clasp on the cape has the gold triangles.
- She doesn't have the triangular bit of material covering her crotch
- The tip of Bardiche is coloured, rather than the plan gun-metal grey.

I've added the movie tag, but this is just from what I can ascertain from this image, so it's not 100%

It's movie Fate. Aside from knowing the artist has been drawing movie Fate as of late, all signs point to it being movie Fate.

An add-on to madcat: The belt is brown rather than red.

Weren't the tops of her thighhighs/stocking different in the movie? I don't recall them being plain and straight-cut...