I can’t help with details, but what you want is some sort of virtual desktop server. In the normal case the Linux desktop software talks to an HDMI or DisplayPort connector with a real monitor. In the case of a virtual server the Nano won’t know that the communications is via networking instead of via a physical monitor. The communications would be to a your laptop running a compatible virtual desktop client.
Vino is the one I see as officially supported, but I have not set this up myself. Someone here may have a URL or suggestions for Vino or other virtual desktop software.
I don’t know the details, but any “virtual” desktop server will not require a “real” monitor. Virtual servers are still a desktop, but they are a desktop purely in RAM and not in hardware. Is this what you want?
If you just want a text mode connection, then there is no need for extra software. ssh runs text mode remote login without anything special.
But yet I will have to connect the Jetson to another device in order to use it, and I want to know if there is a way to do so without the GUI, I mean, is it possible to run commands on the Jetson with another device if I’m not using the headless setup?
Yes. Text mode (command line) is very very powerful and simple to use. You can use ssh over a network to do this. If your host is Linux, then it will have ssh by default. If Windows, then you might need a client like PuTTY for ssh access. Anything you can run on a command line terminal can be run over ssh. No graphical mode required.