Police earlier today revealed the names of the two others killed in the crash as Doc animal threats biodiversity ranger Scott Theobald, of Twizel, and experienced ranger Paul Hondelink, also of Twizel.
Meanwhile the lead investigator has described the crash scene as like a "jigsaw puzzle" with wreckage strewn about 1km from where the helicopter hit the ground.
The helicopter was believed to have crashed minutes after takeoff and all but the blades and a gearbox were destroyed in an intense blaze.
- 'We just lost so much': Tribute to Doc workers
- Firefighters could only watch
- 'Nothing to suggest foul play': Names of heli crash victims released
The crash came less than three months after Mr Wallis' brother and fellow pilot Matthew Wallis was killed in a helicopter crash in Wanaka.
All three occupants of the Hughes 500 died when it came down about 1500m from the airport yesterday.
At a press conference in Wanaka this afternoon, Jonathan Wallis said Nick was "passionate about what he did".
"It could have been any of us (brothers) in that helicopter and that is not lost on us."
"Nick was larger than life in a literal context. He was 6ft 6, he was 120kg. He was effervescent. Nothing was ever a problem."
The family was now dealing with the second tragedy in three months.
"It is cruel that it is not quite three months since Matthew's death, not far from here.
"Of course it makes it doubly hard. That is difficult. We were a very close family. It makes it very hard."
Mr Wallis said the brothers talked a lot together and that he and brother Toby had both spoken to Nick that morning.
He said they were obviously grieving for their own family, "but also for Paul and Scott".
"Paul and Scott are senior rangers who form part of an elite taskforce team that work through the South Island and have for some time.
"This is not a new operation, it is a day to day operation that has been carried out for a very long time."
The other surviving brother, Toby Wallis, said aviation was "in our blood".
"We've been doing it since the early 60s, we're not going to stop flying. We'll keep going.
"If someone has an accident on the road you don't stop driving. It'll be tough to keep going. He was a great little brother."
Conservation Minister Eugenie Sage said Scott and Paul were each conservation legends and pioneers in their respective fields.
It was too early to say what had happened to cause the crash, but at this stage the focus was on getting Nick, Paul and Scott back to their family.
Transport Accident Investigation Commission (TAIC) lead investigator Barry Stevenson said the crash scene was like a "jigsaw puzzle", and wreckage was spread 1km from where the helicopter hit the ground.
"We have found pieces in different places and we just have to figure out they got there and put it all together again."
There had been an "intense fire" where the helicopter hit the ground and all that was left was "blades on top and pieces of the gearbox on the inside".
The ammunition in the helicopter would have exploded.
"We have found significant amounts of ammunition away from the wreckage."
It was believed the helicopter crashed only minutes after take off.
The investigation was expected to take some time and the target for completion was typically about 12 months.
As part of the investigation they had been given CCTV and video footage from around the airport.
Investigators arrived in Wanaka about 10pm last night and have been on site since 9am this morning.
Department of Conservation director-general Lou Sanson said Mr Wallis had such a part in what Doc did.
Doc and the Wallis family were "linked at the hip", and had been for a long time.
"Nick was just incredible."
Mr Sanson had known Paul Hondelink since 1980, and said he had invented a helicopter programme for tahr culls in conjunction with the Wallises.
"Between the Wallises and Paul they did a lot to protect and increase the biodiversity of the area.
"Scott was the pioneer of predator dogs, the first in the world. Where he worked kiwi numbers went up and when he left they went down. There are thousands of birds on our islands because of what he did.
"Paul had just left Wanaka eight weeks ago to run this tahr control programme.
"It's incomprehensible."
"In that helicopter were resources we will never ever replace. You can't beat 47 years of experience."
Jonathan Wallis said it was "fortunate in Wanaka that we do support each other. Wanaka has a rural heart and people are supporting us."
He said it was important to understand aviation was not dangerous but it did carry inherent risk, and "you have to mitigate that risk".
"What they were doing was a very calculated, experienced daily operation.
"For us aviation is a way of life and unfortunately it can be very unforgiving."
