If you have the Nest Aware or Nest Aware Plus subscription (and not the per-camera 1st Gen Nest Aware subscription), all you need to do is add your new camera to the Google Nest app or Google Home app to the same Google Nest "home/structure" as your Nest Aware subscription.
However, if you do have the older per-camera 1st Gen Nest Aware subscription, you can get another 1st Gen Nest Aware subscription only if your new camera works in the Google Nest app; if your new camera works in the Google Home app, then you can cancel your 1st Gen Nest Aware subscription and get the newer Nest Aware or Nest Aware Plus subscription that applies to all cameras and doorbells in the same Google Nest "home/structure".
Perfect, we're glad to hear that! As we got our resolution here, I'm going to mark this thread as complete. I'll be locking this thread if we won't hear back from you again in 24 hours. Should that happen, feel free to create a new one if you have more questions or have other concerns in the future.