Connect a display via HDMI (TV is fine), and see what is going on during bootup of the Nucleus. This might be defective ethernet port (can happen if port got hard preasure), or it could be failing M.2 SSD.
You have my sincerest apologies for the delayed response here, we’ve been dealing with a higher-than-usual volume following our release and we’re working as quickly as we can to get back to everyone.
I did see that your Nucleus was online ~30 minutes ago, are you still running into issues still? If so, @Tor_Gunnar_Berland is steering you in the right direction with plugging your Nucleus into a monitor via HDMI.