No, you need to have a host PC with Ubuntu 18.04 to install the SDK manager, then use it to flash your Xavier NX via the JetPack.
If your NX is a SD card version, then you can refer to SD Card Image Method at JetPack SDK 4.6.1 | NVIDIA Developer to prepare tje SD card for your device.
@kayccc Thanks for your reply. There are some scenarios in which we can’t connect jetson to the host pc directly. Jetson is deployed in a remote location.