To follow a device by its BD address:
nrfutil ble-sniffer sniff --port <serial_port> --follow <BD_address>
To follow a device by name:
nrfutil ble-sniffer sniff --port <serial_port> --follow-by-name <name>
To follow a device by its BD address:
nrfutil ble-sniffer sniff --port <serial_port> --follow <BD_address>
To follow a device by name:
nrfutil ble-sniffer sniff --port <serial_port> --follow-by-name <name>