A member of Britain's team that finished fourth in the inaugural Olympic Sevens tournament in Rio de Janeiro in 2016, Fisher said New Zealand's experience in finishing second to Australia would serve as fuel for this year's effort.
She said with six World Series titles, two Sevens Rugby World Cups and a Commonwealth Games title, the only thing missing from their collection was an Olympic gold title.
"I think in the game of Sevens, especially at the moment with Covid, it's anybody's, however, I cannot fault New Zealand because they have always been ahead of the game," Fisher told The Rugby Paper.
"A Kiwi will always come back hard if you've hit them, so the fact that they lost to Australia in Rio will give them that edge to succeed and be on a mission. Missing out last time will have really hurt them.
"What's been impressive is they have kept their form. New Zealand know how to win big games, and success breeds success.
"Some of the other nations could maybe challenge them, and GB could be one of them, but I just feel we are not so used to having that winning mentality and dealing with the pressure and holding together when it counts," she said.
Fisher, 37, was keen to be in Tokyo, but injury denied her. The loss of her experience, along with another Rio veteran, Katy Daley-McLean, who has retired, will impact on the British side.
"I think we are lacking a bit of experience if I am honest. Without crowds, it might be easier not to have experience though, because if you don't have to deal with the crowd and the expectation, it takes a bit of pressure off.
"It's little things like the comms [communications] are clearer because there is no one drowning out the noise. You can become really isolated on a Sevens pitch when you cannot hear each other and with a young squad that can be detrimental," she said.
Fisher felt the United States would give New Zealand a contest with the quality of their athletes.
"They started to emerge on the World Series last year, and they have always been an amazing, talented team, like the boys, but they have never really had the killer mindset to go out and win games. If they can get that sorted out, they could be a team to look out for.
"Australia are up there, but they are a bit of an unknown entity with Ellia Green not selected," she said.