The GreenAnt Nest Servers will soon be supporting end-to-end, client-side encryption.
This means that you can create and store a password using the desktop, iOS or Android NextCloud client and then encrypt specific folders. These folders will then be fully encrypted at-rest on the Nest Servers.
You can read more about how this encryption is implemented here.
This type of client-side encryption means that a third party can't access your encrypted files (including the administrator of the Nest server).
This is a new feature of Nest and is currently in beta, so we do advise familiarising yourself with its limitations and trying it on a subset of files first.