Rickards was acquitted but the operation uncovered disturbing details about aspects of police culture, the obstruction of justice, and of alleged sex attacks in 1980s Bay of Plenty.
This afternoon, police top brass honoured Nicholas, and she in turn thanked senior officers for whom the day was especially poignant.
She paid tribute to Superintendent John "Pricey" Price, who worked on Austin for a year and was shortly off to a new role in Canterbury, and to Deputy Commissioner Mike Clement.
"That team were the ones that restored my faith in the New Zealand police and that's why when I was asked to be patron, I never hesitated, because of what they did for me and my family," she said.
In an emotional speech, Ms Nicholas revealed how attached she'd grown to the new group of recruits.
"It is with a heavy heart that our time together has come to an end. But it is with a very proud heart that I stand here today and say, wherever your journey within the New Zealand police force takes you, always, always remember to stand tall ... and stand strong."
Ms Nicholas also told reporters she'd had fun as patron of Wing 290.
"As patron, you kind of become the boss, which is really neat. And I could go anywhere, do anything. I could run the joint if I wanted to. Nobody bothered to tell my husband that," she quipped.
"It should have come in writing, eh?"
Ms Nicholas said she and her husband Ross and son Luke went to Manfield racing circuit and took part in a driving skills course with recruits.
She also visited the Cuba Street Carnival with recruits and attended firearms training.
She said the 18-week training course transformed people.
"They actually end up finding themselves and who they are, and acknowledging the reasons why actually we're here and why we want to be the best copper we can. Nobody can train that. That just comes. And this group is pretty special."
The new constables included Sean McGillivray, a war veteran who served in Afghanistan four years ago.
"I felt like my career in the army had run its course. I'd done what I'd joined for and I was looking for a new challenge, something rewarding and getting back into, and being part of, the community again," Mr McGillivray said.
He was in a counter-terrorism unit known as The Commandos working under the SAS. And he said he was pleased a former comrade had joined him at police college this year.
Mr McGillivray said the police had deployed overseas in recent years, such as in East Timor, and if offered a deployment abroad he'd seriously consider it. But he was looking forward to learning the ropes for now.
"Firstly I just want to get out there on the frontline and learn that job..."
Commissioner Mike Bush said the new cops would be called upon to do things "other members of the community will never have to do" and they would need the support of families and loved ones in the years ahead.
Mr Bush said he was pleased to see half the recruits were women, one-quarter were Maori, and many had existing academic qualifications.
Police minister Michael Woodhouse also spelled out the challenges constables faced but said New Zealand's police were among the most-respected law enforcement agencies on Earth.
Police said Wing 290 recruits came from countries including the UK, South Africa and China, and some had degrees disciplines including law, biomedicine, psychology, and applied science.
Last month, Ms Nicholas was named Anzac of the Year, and Governor-General Sir Jerry Mateparae presented her with the award.
