Jetson nano 2G install on 4G carrier board

In order to use M.2 wifi module on Jetson nano 2gb, may I put the 2GB SoM on 4G carrier board ?

Another question, is the 2gb SoM connector pinout matrix (260pin) as same as 4G SoM, and how can I build my own carrier board?

Yes, the 2GB module can be used on carrier board of 4GB devkit. You can follow the product design guide of Jetson nano in DLC to make your design.