There are a few version managers for node.js respecting .node-version file:
- avn – Automatic Node Version Switching
- nodenv – Yet another version managers
- asdf – Extendable version manager with support for Ruby, Node.js, Elixir, Erlang & more, provided you configure it accordingly
- nvs – Node Version Switcher
There may be some other version managers, but I’m not aware of them.
I don’t know which particular version manager Atom uses. nodenv have more stars on GitHub, but avn looks more mature and better maintained for me, not to mention its compatibility with both n and nvm.