By default NX uses system accounts so there is no need to create any NX account so there is no need to use the "nxserver -useradd username" for each user already defined on your system. The following keys in the server /usr/NX/etc/server.cfg configuration file govern this behaviour:

EnableUserDB = "0"

EnablePasswordDB = "0"

then sshd will be used for authentication. That way any user able to login over SSH can login over NX.

If you don't want every user on the system to have access via NX, for this purpose you should set:

EnableUserDB = "1"

EnablePasswordDB = "0"

In this way the server will only allow access to those system users listed in the NX users DB ('/usr/NX/etc/users.db').

Please see also:

https://www.nomachine.com/AR10B00044

for more information about PAM authentication and NX.