I accidentally plugged 12v into the 5v GPIO input

[linuxdev]

GPIO is normally 3.3V, not 5V, but there may be a jumper which selects between 3.3V (default…not sure about jumpers on a Nano, but many other Jetsons have a level select jumper) and 1.8V. I am only guessing, but probably something fried on the carrier board, including the level shifter. This is one of the rare cases where it might have also fried something in the module itself, although I suspect the module is ok. In addition to the level shifter it is also likely that some of the power supply rails were lost. I don’t think it is worth your time to try to fix this. I’ll suggest that you don’t throw the old unit out, and unmount the module to try later, but purchase a new unit. You could find that the module itself still runs correctly on the new carrier board (which you cannot purchase separately), so you’d have one good carrier board and perhaps two working modules.