user-1: I have often been told that nirvana is not a state or entity, because there are no real states or entities in Mahayana Buddhism. 
If so, is that nirvanisation (a word I've seen for the process of coming to enlightenment) a state for those that undergo it?

user8157: Nirvana cannot be a process because this would make Nirvana 'conditioned'. 
Nirvana is a state (dhamma; ṭhānaṃ) or a sense object/base (ayatana; Udana 8.1). 

There is, bhikkhus, that base (ayatana) where there is no earth, no water, no fire, no air; no base consisting of the infinity of space, no base
  consisting of the infinity of consciousness, no base consisting of
  nothingness, no base consisting of
  neither-perception-nor-non-perception; neither this world nor another
  world nor both; neither sun nor moon. Here, bhikkhus, I say there is
  no coming, no going, no staying, no deceasing, no uprising. Not fixed,
  not movable, it has no support. Just this is the end of suffering. Ud
  8.1

'This Dhamma that I have attained is deep, hard to see, hard to realize, peaceful, refined, beyond the scope of conjecture, subtle,
  to-be-experienced by the wise. But this generation delights in
  attachment, is excited by attachment, enjoys attachment. For a
  generation delighting in attachment, excited by attachment, enjoying
  attachment, this/that conditionality & dependent co-arising are hard
  to see. This state (ṭhānaṃ), too, is hard to see: the calming of all
  fabrications, the relinquishment of all acquisitions, the ending of
  craving; dispassion; cessation; Nibbana. MN 26

ṭhāna
standing; the act of standing, being fixed or stationary; continuance.
  a place; a locality; a spot; a site; a location; a suitable place; a
  worthy object. region, sphere; metaphysical or spiritual state.
  situation; station; office; position. position; state. occasion; case,
  occurrence; matter. quality; attribute, characteristic. ground, basis;
  reason, cause. stance; standpoint; condition.


-1: <p>I have often been told that nirvana is not a state or entity, because there are no real states or entities in Mahayana Buddhism. </p>

<p>If so, is that nirvanisation (a word I've seen for the process of coming to enlightenment) a state for those that undergo it?</p>
 8157: <p>Nirvana cannot be a process because this would make Nirvana 'conditioned'. </p>

<p>Nirvana is a state (<em>dhamma</em>; <em>ṭhānaṃ</em>) or a sense object/base (<em>ayatana</em>; Udana 8.1). </p>

<blockquote>
  <p><em>There is, bhikkhus, that <strong>base</strong> (<strong>ayatana</strong>) where there is no earth, no water, no fire, no air; no base consisting of the infinity of space, no base
  consisting of the infinity of consciousness, no base consisting of
  nothingness, no base consisting of
  neither-perception-nor-non-perception; neither this world nor another
  world nor both; neither sun nor moon. Here, bhikkhus, I say there is
  no coming, no going, no staying, no deceasing, no uprising. Not fixed,
  not movable, it has no support. Just this is the end of suffering. Ud
  8.1</em></p>
  
  <hr>
  
  <p><em>'This <strong>Dhamma</strong> that I have attained is deep, hard to see, hard to realize, peaceful, refined, beyond the scope of conjecture, subtle,
  to-be-experienced by the wise. But this generation delights in
  attachment, is excited by attachment, enjoys attachment. For a
  generation delighting in attachment, excited by attachment, enjoying
  attachment, this/that conditionality &amp; dependent co-arising are hard
  to see. This <strong>state</strong> (<strong>ṭhānaṃ</strong>), too, is hard to see: the calming of all
  fabrications, the relinquishment of all acquisitions, the ending of
  craving; dispassion; cessation; <strong>Nibbana</strong>. MN 26</em></p>
  
  <hr>
  
  <p><a href="https://suttacentral.net/define/%E1%B9%ADh%C4%81na" rel="nofollow noreferrer">ṭhāna</a></p>
  
  <p>standing; the act of standing, being fixed or stationary; continuance.
  a place; a locality; a spot; a site; a location; a suitable place; a
  worthy object. region, sphere; metaphysical or spiritual state.
  situation; station; office; position. position; state. occasion; case,
  occurrence; matter. quality; attribute, characteristic. ground, basis;
  reason, cause. stance; standpoint; condition.</p>
</blockquote>
