Hello Joshua,
Thank you for reaching out and I am happy to help!
The Nginx+Memcached caching method in the W3 Total Cache for the Page Cache is selectable in the options if you are on the Nginx server and you have PHP Memcached installed and enabled in your environment.
I can see that the Nginx is used, so please check and confirm that the PHP Memcached is installed and enabled on your server.
Thanks!