What translation variants exist of Mūlamadhyamakakārikā 25:19-20? The verses in question are from Nāgārjuna's Mūlamadhyamakakārikā chapter 25 on an examination of nirvana.
Mūlamadhyamakakārikā 25:19–20
न संसारस्य निर्वाणात् किं चिद् अस्ति विशेषणं
na saṁsārasya nirvāṇāt kiṁ cid asti viśeṣaṇaṁ
न निर्वाणस्य संसारात् किं चिद् अस्ति विशेषणं। १९
na nirvāṇasya saṁsārāt kiṁ cid asti viśeṣaṇaṁ| 19
निर्वाणस्य च या कोटिः।कोटिः। संसरणस्य च
nirvāṇasya ca yā koṭiḥ koṭiḥ saṁsaraṇasya ca
न तयोर् अन्तरं किंचित् सुसूक्ष्मम् अपि विद्यते। २०
na tayor antaraṁ kiñcit susūkśmam api vidyate| 20
There are two mainstream Mulamadhyamakakarikas (hereafter MMK). There might be one in manuscript form recently dicovered that I am unaware of, but there are two that I am aware of, and they are the Sanskrit reconstructed from Venerable Candrakirti's commentary (which might actually be from Tibetan), and the Chinese version with the nested commentary by Venerable Vimalākṣa. The Chinese source text to do with the Sanskrit you provided is:

涅槃與世間無有少分別世間與涅槃亦無少分別涅槃之實際及與世間際如是二際者無毫釐差別
(T1564.35c27)

In the following list, &quot;Skt&quot; means &quot;from Sanskrit,&quot; &quot;Ch&quot; means &quot;from Chinese,&quot; and &quot;Tb&quot; means &quot;from Tibetan.&quot;
INADA (Skt):

Samsara (i.e., the empirical life-death cycle) is nothing essentially
different from nirvana. Nirvana is nothing essentially different from
samsara. The limits (i.e., realm) of nirvana are the limits of
samsara. Between the two, also, there is not the slightest difference
whatsoever.

JONES (Skt):

There is not the slightest difference of cyclical existence from
nirvana. There is not the slightest difference of nirvana from
cyclical existence. The full extent of nirvana is the full extent of
cyclical existence. There is not slightest interval between them.

KALUPAHANA (Skt):

The life-process has no thing that distinguishes it from freedom.
Freedom has no thing that distinguishes it from the life-process.
Whatever is the extremity of freedom and the extremity of the
life-process, between them not even a subtle something is evident.

MCCAGNEY (Skt):

There is no distinction whatever between saṃsāra and nirvāṇa. There is
no distinction whatever between nirvāṇa and saṃsāra. The limit of
nirvāṇa is that of saṃsāra. The subtlest difference is not found
between the two.

SPRUNG (Skt):

There is no specifiable difference whatever between nirvāṇa and the
everyday world; there is no specifiable difference whatever between
the everyday world and nirvāṇa. The ontic range of nirvāṇa is the
ontic range of the everyday world. There is not even the subtlest
difference between the two.

STRENG (Skt):

There is nothing whatever which differentiates the existence-in-flux
(samsara) from nirvana; And there is nothing whatever which
differentiates nirvana from existence-in-flux. The extreme limit
(koti) of nirvana is also the extreme limit of existence-in-flux;
There is not the slightest bit of difference between these two.

STCHERBATSKY (Skt):

There is no difference at all Between Nirvana and Samsara. There is no
difference at all Between Samsara and Nirvana. What makes the limit of
Nirvana Is also then the limit of Samsara. Between the two we cannot
find The slightest shade of difference.

ROBINSON (Skt):

Samsara has nothing that distinguishes it from nirvana; nirvana has
nothing that distinguishes it from samsara. The limit of nirvana is
the limit of samsara; there is not even the subtlest something
separating the two.

BOCKING (Ch):

Between nirvana and the world There is not the slightest distinction
Between the world and nirvana There is not the slightest distinction.
The real limit of nirvana And the limits of this world Between these
two limits There is not the least distinction

BATCHELOR (Tb):

Samsara does not have the slightest distinction from Nirvana. Nirvana
does not have the slightest distinction from Samsara. Whatever is the
end of Nirvana, that is the end of Samsara. There is not even a very
subtle slight distinction between the two.

DOCTOR (Tb):

Cyclic existence is not the slightest bit Different from the
transcendence of suffering Transcendence of suffering is not the
slightest bit Different from cyclic existence. That which is the
condition of transcendence Is the condition of cyclic existence as
well. Between these two there is not The slightest bit of difference.

GARFIELD (Tb):

There is not the slightest difference Between cyclic existence and
nirvana. There is not the slightest difference Between nirvana and
cyclic existence. Whatever is the limit of nirvana, That is the limit
of cyclic existenence. There is not even the slightest difference
between them, Or even the subtlest thing.

GOLDFIELD (Tb):

Samsara is not the slightest bit different from nirvana. Nirvana is
not the slightest bit different from samsara.  The true nature of
nirvana Is the true nature of samsara, And between these two There is
not even the tiniest, subtlest difference.

HAGEN (paraphrase):

Nothing whatever distinguishes samsara from Nirvana. Nothing whatever
distinguishes Nirvana from samsara. Whatever is the limit of Nirvana
is also the limit of samsara. There is not even the subtlest
difference between them.

NISHIJIMA (paraphrase):

Without leaving the process of wandering, it will become leaving
Nirvana. It does never suggest that we have been given up by Nirvana,
Not belonging to Nirvana, is leaving from the wandering. It does never
suggest that we have been given up by Nirvana, What is included by
Nirvana is just Time, And the Time is also belonging to the wandering
life of ups and downs. The two kinds of substances, that is, Time and
the wandering life of ups and downs, Seems to be as if they were
nothing. Then something excellently delicate is recognized very
clearly...

Two of the &quot;translations&quot; that Korin compiles are paraphrases, not translations. All of the above material is from MMK study notes from Venerable Korin available at https://abhidharmakosa.wordpress.com/.
There is one more translation for me to add.
CAOIMHGHIN (Ch)

Between nirvāṇa and the world, there is not the slightest
differentiation. Between the world and nirvāṇa, there is also not the
slightest differentiation.
From the true apex of nirvāṇa to the apex of the world, like this,
there are two apices with not a sliver of difference between them.