I have a Chord Qutest. It only registers in as being connected to the Core via USB. Mine is connected to an imac as Core, but I don’t see how it could register as an endpoint via a BNC cable. Have you tried connecting via USB?
The Qutest can work direct from the Core or downstream of an endpoint. It will work both ways, but will only show as a connected core component via USB.
I don’t use a Nucleus or NAS. You should be able to connect the NAS to the Nucleus over the network. I do not suggest doing so via Wifi, but by Cat Ethernet Cable. We have different setups, but I have two house systems, and ethernet is how I made the connection to the one system away from the office. Some people have complained about using NAS systems.