Nim 0.11.2 is in Debian Unstable - https://tracker.debian.org/pkg/nim - :)
apt-get install nim
There's also a documentation package nim-doc that you can install and browse at file:///usr/share/doc/nim-doc/html/overview.html
If there is any Nim library or application that you think is popular and stable enough to be accepted in Debian please reply to this thread or open an RFP.
How about a Nimble Debian package?
If Nimble was also available on Debian, then nimble can retrieve anything Nim requires.
Or maybe it should be part of the one Nim Debian package (an all-things-Nim Debian package) ??
Either way, great work on getting this into Debian :-)