Go2Linux posted a Nginx guide about redirecting www to non-www
It is not a good idea from the SEO point of view, to have duplicated content. If your content can be accessed from both www.yourdomain.com and yourdomain.com you will have duplicated content. This is true at least for Google and other search engines.Nginx redirect www to non-www
So, to avoid that, you need to forward all your www.yourdomain.com/something to yourdomain.com/something, of course you can do it the other way too.