nginx-rate-limit.conf

       # limit the number of connections to 1 per second and allow to burst to 10
       limit_req_zone $http_x_forwarded_for zone=application:10m rate=1r/s; # For Load Balanced environments
       #limit_req_zone $remote_addr zone=application:10m rate=1r/s; # For Single Instance environments
       limit_req zone=application burst=10 nodelay;
       limit_req_status 429;
       limit_conn_status 429;

       # pass real IP from client to NGINX
       real_ip_header X-Forwarded-For;
       set_real_ip_from 0.0.0.0/0;
       
       server {
         # set error page for HTTP code 429
         error_page 429 @ratelimit;

         location @ratelimit {
             return 429 'Connection Limit Exceeded\n';
         }
       }

you should consider adding a "resolver" param in the http block in case you want to use secure dns resolver with unbound.