The 52-year-old has been wheelchair bound for the past 25 years, after having a stroke while playing rugby in Dunedin in 2000.
It left him with locked-in syndrome - a severe neurological condition where he is conscious and aware, but completely paralysed except for vertical eye movements and blinking.
Ever since, he has spent five days a week in the gym, doing stretches and exercises to keep his muscles toned so he can gain movement, which stops his body from curling up into a foetal position.
And despite his condition, he has gone on to get married, have three children and has won 12 national bodybuilding championships.
But his ultimate goal has always been to walk again.
"It has taken me years of stubbornness, determination, hard work and support from my physio Mark Shirley.
"I am so stubborn that after 25 years, I still will not give up.
"I use my anger and frustration as a fuel to keep going, one day at a time."
"I need to be doing something, rather than sitting around at home doing nothing.
"I need to live longer for my family."
Initially, it took six nurses to stand him up, each holding a different body part so he would not collapse.
Eventually they started putting him in a standing frame for several hours a day.
"One day I suggested to my physio [Mark Shirley] that I could possibly lean over a bedside table on wheels and try to take a few steps.
"Mark got me a walking frame to practice with, and I used to try to walk up and down my hallway every week."
He said the repetitive motion of moving his legs helped to "fire up" the signals to his brain.
"It is sometimes long and tedious and I don’t make huge gains - they’re just tiny gains - but those tiny gains make me more and more determined to achieve my goals."
Now, Mr Chisholm is at the point where he can walk on a treadmill, with very little assistance.
He recalled telling the nurses in hospital after his accident that he would be walking again in 10 years.
"It has taken a bit longer than 10 years, but I will get there.
"This isn’t a party trick - this is my life.
"I will do everything I can to get the old Nick back - the Nick prior to the accident."
While his wife Nicola and their three children were the main inspiration for his achievements, he said his gains were also made possible with the help of ACC, his physio Mark Shirley, SkyFit24 Dunedin gym owners Phil and Angela Chaney and all of his gym assistants over the years.
Mr Chaney said Mr Chisholm was inspiring.
"Where he is now, compared to where he was back then, is chalk and cheese.
"His strength that he’s got is incredible. For someone who doesn’t walk and move, he’s a real inspiration to show what you can do with hard work and determination."
