No.

-:
In 2010, as reported by various sections of the media,
Lawal Keita, a PDP chieftain stated that if a person from
the North did not win the 2011 elections, Nigeria will be
made ungovernable .
Below are links to that effect as reported by the press when
that statement was made.

http://www.pmnewsnigeria.com/2010/10/08/group-wants-
kaita-tried-for-treason/

-:
In April 2011, Reuben Abati slandered Buhari in The
Guardian about same statements of making Nigeria
ungovernable. Buhari sued Abati to court in 2011 for
damaging his name. President Jonathan begged Buhari on
behalf of Abati to settle out of court because Abati might
end up in jail. On 11 July 2012 Rueben Abati and The
Guardian published an unreserved apology to Buhari.

http://newsrescue.com/rueben-abati-retracts-libelous-
invention-linking-buhari-terror-compensates-general-
damages/

[s]-------------------------------------------------------------------------[/s]
http://factchecki.ng/question/did-buhari-promise-to-make-nigeria-ungovernable/

He actually did promise to make Nigeria ungovernable at some time in the past. This idea was first mooted in 2003 when he lost to Obasanjo. Through the years, he went on to release a series of statements threatening the integrity of the country and the lives of it's citizens. You can verify this information by yourself.


I WON'T RECOGNISE OBASANJO’S GOVT SAYS GENERAL BUHARI
“Buhari had, shortly after the declaration of President Obasanjo as the winner of the last presidential elections vowed to make the country ungovernable by organising mass action to protest the outcome of the election.”

P. M News, 19 June 2003


BUHARI: DON'T RECOGNISE OBASANJO AFTER MAY 29
“I have no hesitation in rejecting the outcome outright. In the light of the clear case of rape on our democracy, I would plead with the international community not to recognise a government that is being formed on the basis of this contraption because such a government lacks credibility and legitimacy”

“Otherwise, there would be no government from 30th of May in this country.”

Buhari
(This Day, 24 April 2003)


2015: WE ARE BATTLE READY – BUHARI
“We have decided, together with the party leaders, that by the year 2015, God willing, it’s either the government does justice in the conduct of elections as always claimed by them or it will be a fierce bloody battle.”

“God willing, by 2015, something will happen. They either conduct a free and fair election or they go a very disgraceful way.”

- Buhari
(Leadership, 15 May, 2012)


2015 WILL BE BLOODY IF - BUHARI
“If what happened in 2011 should again happen in 2015, by the grace of God, the dog and the baboon would all be soaked in blood.”

– Gen. Buhari
(Vanguard, 12th May, 2012)

mulante:
He actually did promise to make Nigeria ungovernable at some time in the past. This idea was first mooted in 2003 when he lost to Obasanjo. Through the years, he went on to release a series of statements threatening the integrity of the country and the lives of it's citizens. You can verify this information by yourself.

-:
I WON'T RECOGNISE OBASANJO’S GOVT SAYS GENERAL BUHARI
“Buhari had, shortly after the declaration of President Obasanjo as the winner of the last presidential elections vowed to make the country ungovernable by organising mass action to protest the outcome of the election.”

P. M News, 19 June 2003


BUHARI: DON'T RECOGNISE OBASANJO AFTER MAY 29
“I have no hesitation in rejecting the outcome outright. In the light of the clear case of rape on our democracy, I would plead with the international community not to recognise a government that is being formed on the basis of this contraption because such a government lacks credibility and legitimacy”

“Otherwise, there would be no government from 30th of May in this country.”

Buhari
(This Day, 24 April 2003)

When we say "he promise to make Nigeria un-governable" w, we assume he is threatening violence against Nigeria.

With all sense of comprehension, there is no threat of violence in what you wrote above. Buhari only vowed not to recognise the outcome of the election against Obasanjo, which was well rigged.

.:
2015: WE ARE BATTLE READY – BUHARI
“We have decided, together with the party leaders, that by the year 2015, God willing, it’s either the government does justice in the conduct of elections as always claimed by them or it will be a fierce bloody battle.”

“God willing, by 2015, something will happen. They either conduct a free and fair election or they go a very disgraceful way.”

- Buhari
(Leadership, 15 May, 2012)


2015 WILL BE BLOODY IF - BUHARI
“If what happened in 2011 should again happen in 2015, by the grace of God, the dog and the baboon would all be soaked in blood.”

– Gen. Buhari
(Vanguard, 12th May, 2012)

We just arrived 2015, so this is out of question.
However, I believe that injustice of whatever kind must be resisted by any mean necessary.

You asked a question and I answered the question you asked. The question I believe is "Did Buhari promise to make Nigeria ungovernable?". My answer is "Yes, he did." I gave you a reference to validate my answer. Now, the time he made that statement and the persons the starement was directed to is immaterial to the question you asked. The fact remains that he did make such promise.

It remains to be seen if there's a nexus between that vow and the security crisis in the country today but ideas take time to be translated into actions.

That we just arrived 2015 does not render his threats ineffective. If anything, it only means that Gen. Buhari should be watched even closely until the year has come to an end without any regrettable events.