This is what Acharya Nagarjuna has to say about Nirvana and this question in his 25th chapter (Examination of Nirvana) of The Fundamental Verses on the Middle Way: The Text Called Wisdom
25.18 So, when the Transcendent Lord was alive, he
Was neither perceived to be existent
Nor perceived to be nonexistent.
He was neither perceived to be both nor to be neither.25.19 Cyclic existence is not the slightest bit
Different from nirvana.
Nirvana is not the slightest bit
Different from cyclic existence.25.20 Whatever is the limit of nirvana,
That is the limit of cyclic existence.
There is not even the slightest difference between them,
Or even the subtlest thing.25.21 Views regarding his status after his passing; extremes, etc.,
And views regarding the permanent, etc.,
Are grounded upon nirvana, the final limit,
And the prior limit.25.22 Since all existents are empty,
What is finite or infinite?
What is finite and infinite?
What is neither finite nor infinite?25.23 What is identical and what is different?
What is permanent and what is impermanent?
What is both permanent and impermanent?
What is neither?25.24 The pacification of all objectification
And the pacification of all fabrication is peace.
No Dharma was taught by the Buddha
At any time, in any place, to any person.
This is my personal favorite text on Nirvana and one of profound and deep wisdom to my limited mind. 