This is a oh-my-zsh pluginx for python-novaclient. It provides auto-complete for the nova so you don't need to remember all those pesky arguments. To install put the nova folder inside your ~/oh-my-zsh/custom/plugins/ directory and enable it within your .zshrc file.
If you have any issues you can open an issue here. Contributions are always welcome. Once all the subcommands are done I'll be submitting a pull request with oh-my-zsh but it looks like they aren't maintaining anymore so I doubt that'll go too far.