Can NLS parameters be modified at the instance and database levels?

Hi experts,

I'm using Toad 17.1.717.3711 with DB Admin module license.
I log in as sys as sysdba.
When I opened NLS parameters, there are 3 tabs for different levels.
But I can only edit the parameters at the session level, the instance and database levels are uneditable.
It is different from the KB article I found.
I just want to make sure that the NLS parameters can be edited at the instance and database levels or not?

00

They can not. Can you share the KB article so I can correct it?

Hi John,

Here is the KB link.

Thank you for your reply.