Once your application has been processed and approved, you will be sent a letter providing “in principle approval for registration”, which is valid for three months, and details the outstanding proof of identity requirements. This does not mean that you are registered, it means you have met all registration requirements, but only provided the minimum proof of identity evidence with your application (because you were not living in Australia at that time).
Final registration (when you actually get your AHPRA number and can officially work as a nurse) will be subject to you providing the outstanding proof of identity requirements to AHPRA in person. This can be done at any AHPRA office, regardless of which one you sent your application to. The “in principal approval for registration” is valid for three months, so it is advisable to present at an AHPRA office soon after you arrive in Australia.