Here is the software: https://www.nordicsemi.com/Software-and-Tools/Development-Tools/nRF-Sniffer-for-Bluetooth-LE which notably doesn't support the nRF52 dongle
I also found some forum posts from almost a year ago talking about development but no projected timeline... is support for this still under active development? If so, is there any timeline now?
It would just be nice to not have to awkwardly break out UART to do this when there are perfectly good USB data lines...