Nginx limit request method

$request_length: request length

$request_method: request method

$status: HTTP response code (1.3.2, 1.2.2)

$nginx_version: NGINX version

$arg_name: the parameter name in the request

server {
...

 if ($request_method !~* GET|POST) {
            return 403;

        }

or

if ($request_method !~ ^(GET|POST)$ )
        {
            return 403;

       }

}