Yes, it can. I believe that if you use ToT then you have to have nas on every hub that uses ToT. You will likely run into comment form Support that "this isn't supported" but a handy query back to them to provide the reference in the documentation about where that is defined will usually get you past that issue.
It does require some planning though because the nas is the end point for messages with an Alarm subject. So if you have a central place where alarms are further processed, you need to either identify a way to get a copy of the alarm to the central nas or set up nas replication.
Whichever why you decide (or need) to go, consider that there are some significant reliability problems with both courses.
-Garin