Rewrite Rules for NGINX Web-Server

We recently migrated our site from a windows based server over to a linux web server. XML Site map is giving me the following rewrite rules. Where do i add this code?

Since you are using Nginx as your web-server, please configure the following rewrite rules in case you get 404 Not Found errors for your sitemap:
rewrite ^/sitemap(-+([a-zA-Z0-9_-]+))?.xml$ “/index.php?xml_sitemap=params=$2” last;
rewrite ^/sitemap(-+([a-zA-Z0-9_-]+))?.xml.gz$ “/index.php?xml_sitemap=params=$2;zip=true” last;
rewrite ^/sitemap(-+([a-zA-Z0-9_-]+))?.html$ “/index.php?xml_sitemap=params=$2;html=true” last;
rewrite ^/sitemap(-+([a-zA-Z0-9_-]+))?.html.gz$ “/index.php?xml_sitemap=params=$2;html=true;zip=true” last;

The page I need help with: [log in to see the link]