have you tried to re-flash it with SDK Manager or the flashing script in our BSP?
If the bootloader in the QSPI memory on the module is corrupted, which seems very likely in your case,
then flashing only the SD card is not going to help no matter how many times you try.
Yes, that definitely helped! I had problems using SDK manager because no one says that to flash Jetson Nano you MUST use Ubuntu 18. But yes, after SDK flashing new SD images worked well.