If you are using Jetson Nano Developer Kit SD Card Image, the OS have the tendency to hand during startup/boot at the above message (usually around 5-10 minutes mark).
If you have a keyboard attached, pressing any key will "resume" the process.
For me, the process doesn't end even after 3 hours. It seems to be trying to update the OS and components, and maybe I didn't connect to a network thus it is in an never ending loop.
Just switch off the power, and power on again. It will enter the configuration screen almost immediately and eventually load the desktop.