Reviews found Australia's swim campaign at last year's London Olympics unravelled amid a lack of leadership, collapsed morale and animosity between swimmers.
But Nugent, who oversaw Australian swimming's lowest medal haul at an Olympics in two decades, said he had no idea of the cultural failings.
"A lot of these things have come out in reflection," Nugent told reporters in Canberra.
Two separate reviews were released publicly on Tuesday, both condemning swimming's culture and management.
One review cited a "toxic" culture in Australia's swim team at last year's Olympics, saying incidents of "getting drunk, misuse of prescription drugs, breaching curfews, deceit, bullying" were not addressed by team hierarchy.
Claims some swimmers devised an initiation ritual involving the use of sleeping drug Stilnox were being further investigated, with the Australian Olympic Committee warning of likely sanctions for using the banned prescription drug.
Australia's swimmers won just one gold medal, six silver and three bronze at last year's London Games, the lowest tally in the pool since 1992 in Barcelona.
Australia also went without an individual gold medal for the first time since the 1976 Montreal Olympics.
The London team was undermined by a lack of moral authority and discipline which manifested in a "schoolyard clamour for attention and influence", said the Bluestone Review into culture and leadership.
"Situations were left to bleed," the report said.
The festering and lack of leadership caused swimmers to feel alone and without support.
"Swimmers described these Games as the lonely Olympics and the individual Olympics ... swimmers felt undefended, alone, alienated," the report said.
The review said some older athletes saw the storm brewing, with stalwart Libby Trickett admitting she was among them.
Trickett said she heard rumours of swimmers abusing prescription drugs and others being bullied.
"Definitely there were some things that were toxic," Trickett told AAP.
"It wasn't one thing or a particular person that was toxic. It was an unfortunate series of events that led to that outcome."
Trickett backed Nugent to continue as head coach, despite the review finding a disconnect between swimmers and the coach, and also veiled criticism from Australian Sports Commission chief Simon Hollingsworth.
"It is fair to say that the head coach should have oversight over the broad happenings of the team," Hollingsworth said.
The ASC and Swimming Australia commissioned the other report, the Independent Swimming Review, which identified serious management shortcomings.
The review highlighted a lack of clear national vision, poor accountability, transparency and communication, and questionable use of funds.
It also found Swimming Australia's board was unable to deal with issues and did not critically evaluate performance, and made 35 recommendations to improve governance and the high performance program.
Swimming Australia president Barclay Nettlefold said an integrity panel had been created to examine recommendations from both reviews.
"Before we look at winning gold medals, we want to win back the admiration of the nation," he said.