He pleaded guilty to the charges in November and was sentenced in the High Court at Auckland today by Justice Timothy Brewer.
Justice Brewer outlined how, six days before the threats, Nicholas went to Bunnings in New Lynn and bought "various flammable chemicals".
He then went home and spent eight hours constructing a device - a container of chemicals that he put inside a suitcase with a wick attached.
He then went into the Central Park building in his wheelchair.
Justice Brewer said 14 business have offices in the five-storey building and at least 100 people were working there at the time.
Once inside, he got out of his wheelchair, sat on sofa, placed the suitcase at feet and asked to speak to someone who worked for a chemical company on site.
"You said you had a bomb in your suitcase and you would blow yourself up," Justice Brewer said.
Nicholas told people in the building that the bomb was on a timer and "could not be stopped".
The police were called and the building evacuated - apart from three workers who stayed with Nicholas and tried to placate him.
"You set light to a wick protruding from [the] suitcase with cigarette lighter," said Justice Brewer.
"The wick stopped as it reached [the] suitcase."
After his arrest Nicholas told police he intended to blow the building up.
A bomb expert later found that the bomb would never have detonated, but had it been exposed to a "significant heat source" it had "potential to omit toxic fumes" which could have been very harmful.
Justice Brewer said although the bomb did not detonate, the threat Nicholas posed was "real and serious".
"No one knew the capabilities of the device," Justice Brewer said.
"And when police arrived - and i think this is significant - you set fire to the wick.'"
He said the level of premeditation was "high" and the disruption caused to not only the people in the building but police and army bomb experts was major.
The court heard that Nicholas' offending had been an attempt to draw attention to his health and the fact he was not getting adequate help.
The most significant of is many health issues was fibromyalgia, which causes widespread and often constant musculoskeletal pain accompanied by fatigue, sleep, memory and mood issues.
He also had mental health issues, mainly a personality disorder.
However authorities could not intervene without Nicholas' permission.
Justice Brewer said the difficulty in sentencing Nicholas was that any term of imprisonment would be short and the offender would more than likely be back before the courts.
And he could not order the offender to engage with mental health services.
"He will soon be out and unless something entirely unexpected happens, he will be back before the court," said Justice Brewer.
"He has a high risk of reoffending, his record seems to be accelerating.
"I think you realise as do I that I have very limited options for dealing with you."
Alongside this year's bomb threats and the 2013 siege, Nicholas was in November 2014 sentenced to four months' jail when he was caught with a firearm.
In July 2015 he went to the NZ Stock Exchange with a knife and threatened to blow up the building.
For that, he was jailed for two months.
Justice Brewer said Nicholas "continued to present danger to the public".
"Your mental health is not so serious that the authorities can intervene without your consent," he told Nicholas.
"But you are, as a result of the personality disorders, assessed as being of high and continued risk to the public.
"A lot of your offending is your way of attracting attention because you want to be treated - but you disagree with the quality or extent of that treatment you have been offered.
"I cannot do anything about that.
"Ultimately, you are going to have to make your own decisions."
Justice Brewer said there was "no tangible evidence of genuine remorse" from Nicholas.
He set a starting point of 19 months in jail for the recidivist offender, but gave him a discount for his guilty plea.
The final sentence for Nicholas was 14 months in prison.
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