At the moment she is handling league games in Northumberland & Durham Division Three and there are confident predictions among people who know about these things that she'll be at Division One level before the end of next season.
"The fact that Nikki is handling league rugby so soon after starting to referee tells its own story," says Will Halford, Referee Development Officer for the North East and Yorkshire: "And make no mistake, she is very good and her performances have fully justified the rapid increase in the level of games she's been getting."
"It's absolutely brilliant to have someone of her calibre having the desire and commitment to come through the system and have the ambition to get to the highest level. The beauty of the success of Nikki, Helen Ashman from Houghton-le-Spring and another Northumberland girl, Lizzie Butler, in refereeing league rugby matches is that is proves conclusively that women really can handle important, competitive games and share fully in the buzz that comes from being involved in the sport."
Nikki O'Donnell endorses that view and recommends taking up the whistle to any young woman with an interest in rugby, but who does not warm to the idea of hand-to-hand combat.
"My experience in the game since going on the course has been brilliant," she says: "Durham Referees have been really fantastic and I've had people at games on a regular basis to mentor me and give me tips on the areas of my game that I need to improve.
"At clubs the whole experience has been very positive. Officials have also been very supportive in terms of sorting out changing accommodation, making we welcome and generally treating my as they would any other referee, which is perfect. Exactly what I want. I just want to be judged on how I do the job.
"So far as bad language is concerned, players sometimes let their frustrations get on top of them and I understand that from being a player, but I tell them I don't like it and generally they calm down. I've had one or two dust-ups to deal with, but nothing especially serious.
"The amusing part of the job is that every match I handle, the players come up and ask what they should call me - they're so used to saying 'Sir' and don't know whether they should say 'Ma'm'. I reckon they have enough to think about in a game, so I'm very happy with 'Sir'.
And future ambitions? "With any sport, as a player, coach or official, the aim always has to be trying to get to the highest level possible, which in my case would be the Women's World Cup or Six Nations Championship." she says.
"As a short-term goal, I want to do well with the Sharks and keep playing, but also develop as an official with the help of Durham Referees' Society and aim towards the Women's Referee Development Squad by the end of next season. If I can progress down that route and hopefully get more women and girls interested in taking charge of games I'll be very happy."