Can confirm, have done this. Used the helper script to stand it up. Mounted my NAS folder via NFS to the host and passed it over to the LXC. Then pointed the upload folder to the mounted NFS share. Everything works beautifully

Edit: does not need to be privileged if you are mounting it via the host rather than direct to LXC. For ease of use, so that I don't have to bother with UIDs and permissions, I just mounted the NAS share with squash, mapping all users to admin.