http {
    ...
    log_format  main  'ip="$remote_addr" auth="$http_authorization" timestamp="$time_iso8601" upstream="$upstream_addr" '
                      'host="$host" req="$request" status=$status bytes=$body_bytes_sent '
                      'req_time=$request_time uct=$upstream_connect_time uht=$upstream_header_time urt=$upstream_response_time '
                      'ref="$http_referer" ua="$http_user_agent"';
    ...
}

server {
    ...
    location /suggestions/ {
        proxy_pass http://suggestions;
        access_log /var/log/nginx/suggestions.log main;
    }
    ...
}