Previously I have been a user of the related packages mingw64-libnova-devel and mingw64-libnova; which I'm sure were available about 1 year or so ago, which used to be under:
A source package with that name never existed in that project:
$ osc log -D windows:mingw:win64 mingw64-libnova Server returned an error: HTTP Error 404: Not Found Package not found: windows:mingw:win64/mingw64-libnova
Interesting, I must have been miss-remembering. Luckily I managed to find an old Virtual Machine which had my previous work on it. So I've tidied that up, submitted the package and is now available: https://build.opensuse.org/package/show/windows:mingw:win64/mingw64-libnova -- Be Seeing You - Rob. If at first you don't succeed, then skydiving isn't for you.