On what operating systems Nit is available?
Nit can be successfully compiled (with make) and used on Linux distributions (tried on Debian, Ubuntu, Fedora) for 32bit and 64bit architectures; and on other Unix variants (tried on MacOSX and SunOS).
Some people tried to use it on Windows through cygwin but with poor performances. If you really want to use Nit on windows, you can either try to help the port or use some virtual machine.