The comments focusing on your %PATH%
may be relevant, but they only point to a small part of the problem. In this case I think they're more misleading than helpful.
nvm is a
Simple bash script to manage multiple active node.js versions
(bold added)
nvm isn't exactly a standalone program, and (perhaps surprisingly) it isn't written in JavaScript. It's a script written for bash, the default shell on most Linux machines (though it also works with zsh and may work on other related shells like the Bourne shell). On Windows, Git comes with Bash and I strongly suspect when you say "Git CMD" you really mean that Bash shell.
Windows' cmd.exe
is a completely different animal. PowerShell is closer to bash than cmd.exe
, but it's still very different and scripts aren't compatible between the two.
This is a bit like asking why a Perl script doesn't run on Python. They're simply different languages.