If you follow the screenshots below you can set the password expiration to UNLIMITED through the Oracle dbConsole user interface.
Login as SYS (SYSDBA) and click on the “Server” option:
In the “Security” section of this page, click on “Profiles.”
At the “Profiles” page, select “Default” and then click the “Edit” button.
While in “Edit” mode, click the search icon for “Expire” in (days) in the “Password” section.
When the “Select a Value” window opens, select “UNLIMITED” and then click the “Select” button
Click the “Apply” button to modify:
At the “Server/Security/Users” page you will see that the “Expiration Date” column is now empty for the user that owns the NexOSS tablespace as well as SYS and a few others.