The striker credits his former boss with not only improving him as a player, to the extent that he became a regular in Steve Clarke's Scotland squad under his watch, but also for helping him through difficult periods in his life since moving to Easter Road in July last year.
Nisbet lost his father to cancer just a few months after joining the club from Dunfermline while he has also dealt with transfer speculation and scoring droughts – which he says Ross helped him through.
"I spoke to Jack after he left and I have a lot of gratitude towards him," Nisbet said. "He was the one who brought me to the club and made me a better player.
"He also stuck by me in tough times so I have a lot of good things to say about Jack.
"I have no doubt in the future that he will go and get himself a really good job.
"Jack gave me belief and he also helped my all-around game. When I first signed, I was lacking in areas.
"But we worked on things and he improved me a lot.
"Jack gave me the platform to play and stuck by me when I was going through mini-droughts in front of goal.
"He also really looked after me when I had off-field issues. I only have good things to say. I have a lot of time for him."
Nisbet handed in a transfer request last January amid interest from Birmingham City and was dropped from the Hibs starting XI for a spell, but he insists there was no fall-out with Ross – quite the opposite in fact.
"Jack gave me a lot of advice when that was happening. He's been through a lot of it as a manager and he was good with me," he said.
"He did the right thing by me, he took the pressure and limelight off me for a few weeks and then eased me back in.
"It worked wonders for me as after that I got my Scotland call-up and I have been in every squad since.
"I have a lot of time for Jack and Potts. They did a lot for me and I wish them all the best.
"He played a big part in getting me the Scotland call-up and he kept me motivated when times were tough.
"Jack always kept my confidence levels high and he always believed in me.
"I will be forever grateful to him.”
Nisbet insisted the Hibs players are “100 per cent” behind David Gray, who will lead the team for the Hampden showpiece after taking caretaker charge following the departure of Ross at the start of the month.
Having overcome Rangers in the semi-final, he says completing an Old Firm double by beating Celtic to lift the cup would make it all the sweeter.
"We put in a good shift against Rangers. It would be the best way to win it – beating Rangers in the semi and then beating Celtic in the final, the two best teams in the country. It would be a lot more deserving."