Following up on this issue. We are seeing the same thing. Where an Orin Nano flashed through the command line with Jetpack 6 is showing up as an Orin NX.
The Orin Nano and Orin NX share the same pinout.
Therefore, if you build an image with ones configuration, it will probably work in the other.
We image what is happening is that the SD card blob was created using a configuration file for NX, therefore, when it boots it has the NX name all over it. However, it still works since they share the same pinout.
As recommended by Wayne on the post you mentioned, you could try flashing with the SDK manager first, so you can make sure the image you are building/flashing is using all Nano files.
Also, you could try building the SD card blob yourself, and double checking the configuration file used for the image generation, ensuring you use the Nano configuration file.
Please let us know if that helps or if you have further questions.