http://wordpress.org/plugins/bulletproof-security/faq/
This is the full extent of my knowledge regarding Nginx and BPS. Or of course you could convert the .htaccess code to an Nginx Server config code format. And nope I have never messed around with that so I would not be able to provide that code for you.
Does BulletProof Security Work on ALL Nginx Servers / Server Configurations?
If you are using both Apache and Nginx together and Nginx is the frontend webserver and Apache is the backend Server used to process PHP then BulletProof Security will work on this type of combined Server Configuration. If you are only using Nginx then an .htaccess file will not work. Nginx has its own rewrite module – HttpRewriteModule and the mod_rewrite equivalent of an .htaccess file has similar, but different coding and is added to an Nginx Server config file. Note: If you are not familiar with Nginx, then it should be noted that Nginx does not have a PHP module like Apache’s mod_php, instead you either need to build PHP with FPM (ie: php-fpm/fastcgi), or you need to pass the request to something that can handle PHP.