I can't speak to whether it is used more often, but I would bet the java-based Nashorn vm is significantly slower than the c++-based nodejs. In fact, a cursory google search shows this is the case, and it's not even close.
See: http://blog.jonasbandi.net/2014/03/performance-nashorn-vs-no... http://pieroxy.net/blog/2015/06/29/node_js_vs_java_nashorn.h...
(I can't speak to the quality of either of these tests, but the results seem decisive)