You can remove your own nick in headless

If you press backspace too many times, you will start deleting the nickname.

OS: Windows 10
Build: #25320829

Update: OS: Debian 9.x 64-bit(Vmware workstation 14 Player)
Build: #25320829
Problem still occurs, but in a different way, you can't normally backspace like in windows, you need hold right-ctrl then backspace