How to Backup from NAS to cloud

Dear All,
we use an XP PC as file server. On this PC Acronis Online Backup backs up (bachups?)several folders to the Acronis cloud. This happens at night when nobody is there and all the other PC are sleeping.
Now we want us a NAS for the job of just file serving and back uping (backing up? upbacking?). These NAS usually come with a kind of LINUX OS and are managed via a web front end. So I'm afraid we will not be able to install any of the Acronis Online Backup software because it is not Windows, right?

Is there a solution to use the NAS (without a running PC attached)? And how would this work? Is there a know or recomended hardware?

Thanks for helping us.
BR
xdata