I do not believe there is a way to do that. Are these single user machines or shared machines? If single user and they've already got a local account, you can run the authchanger reset to default back to the native login window? If shared and other users may need to be created, I would just explain the behavior change
Are you also using NoMAD or Kerberos SSO once they log in? If you are using either of these in addition to NoMAD Login just for user creation, then you would not lose that ability. They can run separately or in tandem.
The NoMAD or Kerberos SSO menu bar item can keep the user's password in sync without NoMAD Login even being installed.