From what I understand Bower uses npm and as such you can use Nodejitsu.
Support for npm repositories is also a requested feature for Nexus. If you are interested in that, vote on the issue and you might see it implemented in the not too distant future ;-)
In the meantime you can potentially use webjars
Update 2015-03-13: NPM support has been available in Nexus OSS and Pro for a while now. Read more about setting it all up in the documentation. However to clarify the Bower repository format is different from the npm format. The Bower team is hoping to move everything to NPM and stop development and hosting, but that is an ongoing effort.
Update 2016-04-11: The new release of Nexus Repository Manager OSS 3.0 has full support for npm and bower.