nginx.conf

error_log  syslog:server=unix:/var/log/nginx.sock;

http {
    log_format verbose '$remote_addr - $remote_user $host "$request" $status $body_bytes_sent "$http_referer" "$http_user_agent"';

    map $status $loggable {
        ~^[2]  0;
        default 1;
    }

    map $scheme $server_https {
        default off;
        https on;
    }

    access_log  syslog:server=unix:/var/log/nginx.sock verbose if=$loggable;
}

rsyslog-nginx.conf

$AddUnixListenSocket /var/log/nginx.sock

# access log
$InputFileName /var/log/nginx/access.log
$InputFileTag nginx:
$InputFileStateFile stat-nginx-access
$InputFileSeverity notice
$InputFileFacility local6
$InputFilePollInterval 1
$InputRunFileMonitor