Using `stable` is also another way.

  > nvm install stable
  v4.0.0 is already installed.
  Now using node v4.0.0 (npm v2.14.2)

nvm maintainer here: this is true - but please use `node`, since the concept of "stable" and "unstable" has died with the advent of node v4.0 using semver.

All node versions are now stable, and version numbers now communicate breakage, not stability. As it should be.