Unfortunately, I have no experience with Nginx. There are Apache to Nginx converters for .htaccess rules, and the best I make out is they go in some config file.
Here's one such converter:
http://winginx.com/en/htaccess
I couldn't say whether it works or where you might place these rules.
I will say, though, that if you're not building links to your site with both www and non-www, and others aren't linking to your site that way, and you've set your preferred domain in Google and you use only www or non-www on your own site, it should be an insignificant point in most cases.
If you wish to look into it further, I think this could be of some help:
http://www.farinspace.com/wordpress-nginx-rewrite-rules/
It looks like it'll give you the ability to use permalinks (if you can't) and possibly enforce the www/non-www with visitors.
I've been using nginx for my personal servers for some times and I love it!
No, it works in a different way, but you can find some online .htaccess to nginx rewrite converters (i've not tested them since don't use that much).
In Debian/Ubuntu, the directory structure is the same. What the a2ensites command does is create a symlink to your file in the sites-enables folder, so I just usually do something like: cd /etc/nginx/sites-available vi mysite.com cd ../sites-enabled/ ln -s ../sites-available/mysite.com . # create symlink nginx -t # to check the nginx config syntaxis service nginx reload # reload config files
You can configure it so the document root (root directive in nginx) is whatever you want. I'm used to create users for everysite and host the files in /home/user/www folders