Yeah @kurulumu-Net you can change port in config.json in one of the NodeBBs and change to the same port in the proxy-pass part of the corresponding nginx config.
Default port is 4567, one will need to be changed.
My server have install Plesk, because I want run somethings on my server.
I install nodebb by command line, and ready to run at localhost:4567
Pls follow with image to config nodebb on plesk.