My bad, i was unclear. I don’t think chromecast can source NAS. In my experience you can stream to chromecast via a device player, like VLC.

WebOS can also play files direct from a NAS though, but that obviously involves downloading in full to the NAS before playing.

Used to be able to do this before they made you consent to sharing your data for ad purposes. I use a chromecast and a NAS. No issues so far.