The NAS-ID configured in the Radius Server on the Aruba Controller is the name NAS-ID that is seen in the NPS event viewer and can be referenced in the remote access policy.
If you have two different SSIDs and you want to differentiate between them, on the Aruba Controller you will need to (1) Create a new Radius server exactly like the previous one, except the NAS-ID is different (2) Create a new server group and put that new server in it (3) Add that server group to the new AAA profile for the Virtual AP for that new WLAN:
Radius Server Config on the Aruba Controller:
How it looks in the Event Viewer on the NPS server:
How you make it a condition in your remote access policy on NPS: