When Nibbana is realized in the body, it is called Sopadisesa Nibbana Dhatu.
Nibbana is that which is unconditioned, it is neither created nor formed, hence it is therefore permanent.
As we are conditioned to exist as a human being, we should be able to "realise" Nibbana according to the above by our own minds.
So what is the difference between Nibbana and Buddha?
If we can experience Nibbana as an individual, does that mean Nibbana is within every one of us.....hidden/concealed.....but then does that mean Nibbana is in parts as it is realized by each individual or do we realized Nibbana as a whole?
We could say Nibbana is perfection as it is neither created nor formed, therefore permanent.....this is what we want to be, is it not.....so how is this any different to that of the Buddha itself?.....So does that not also make us all as Buddhas too?.....potentially!