If you want to set some alias name to installed node version, do:

nvm alias <name> <version>

Similary to unalias, do:

nvm unalias <name>

A proper usecase would be, if you want to set some other version than stable version as default alias. default aliased versions are loaded on console by default.

Like:

nvm alias default 5.0.1

Then every time console/terminal starts 5.0.1 would be present by default.

Note:

nvm alias # lists all aliases created on nvm