If you have connected your Jetson Nano via HDMI to your TV it can happen, your menu and desktop font is much too small to read.
I tried to change the settings, but I was unable to read anything. After reading a while about this problem on Stackoverflow and on other websites, I found a well working solution on the Nvidia developer forum.

I just had to edit the File:

 /usr/share/lightdm/lightdm.conf.d/50-xserver-command.conf 

I added ” -dpi 96 ” to the last line and reboot the system. Now everything works as expected.

Source:
https://forums.developer.nvidia.com/t/menu-and-desktop-font-text-too-small-to-read/158905