Nicolson made her professional debut on 3 March 2022, at the Pechanga Resort & Casino in San Diego, USA, against the American fighter Jessica Juarez. Nicolson won by unanimous decision. On 15 October 2022, Nicolson defeated Krystina Jacobs by unanimous decision to win her first professional belt, inaugural
Commonwealth female featherweight championship in Brisbane, Australia. The outing was her first pro-fight on home soil. On 4 February 2023, Nicolson defeated
Tania Alvarez by unanimous decision to win
WBC female Silver featherweight championship at the
Hulu Theater in New York, USA. On 15 September 2023, Nicolson challenged Sabrina Maribel Perez for the interim WBC featherweight championship at
Auditorio Fausto Gutierrez Moreno in
Tijuana, Mexico. She won the fight by unanimous decision. On 25 November 2023 at
3Arena in Dublin, Ireland, Nicolson retained her interim WBC featherweight championship via ninth-round technical knockout against
Lucy Wildheart.
WBC women's featherweight champion Nicolson vs. Mahfoud In January 2024, it was announced that Nicolson would face
Sarah Mahfoud for the vacant WBC female featherweight title in Australia. Early March 2024, the fight was scheduled for 6 April 2024 at
Fontainebleau Las Vegas in
Winchester, Nevada, USA Nicolson defeated Mahfoud via unanimous decision (100-90, 100-90, 99-91) and took the vacant title.
Nicolson vs. Vargas Nicolson made the first defence of her WBC featherweight title against Dyana Vargas at
Wells Fargo Center in Philadelphia, Pennsylvania, US on 13 July 2024, winning the fight by unanimous decision with all three ringside judges scoring the contest 100-90.
Nicolson vs. Chapman Nicolson made the second defence of her title against the previously unbeaten
Raven Chapman at
Kingdom Arena in
Riyadh, Saudi Arabia, on 12 October 2024, in what was the first women's world title boxing fight held in the country and the first women’s bout to feature on a
Riyadh Season show. She won the fight by unanimous decision, with scorecards of 98-92 and 99-91.
Nicolson vs. Brown Nicolson made the third defence of her WBC featherweight title against
Tiara Brown at
Qudos Bank Arena in Sydney, Australia on 22 March 2025. She lost by split decision.
Super-bantamweight Dropping down to campaign at
super-bantamweight, Nicolson returned to the ring against Carla Camila Campos Gonzales at
Manchester Arena, Manchester, England, on 5 July 2025, stopping her opponent in the second of their scheduled eight-round contest. On 23 August 2025, she stopped Urvashi Singh in the second round at Fortitude Music Hall in
Fortitude Valley, Queensland, Australia, to win the vacant
IBF Intercontinental female super-bantamweight title.
Interim WBC super bantamweight champion Nicolson vs. Luna Nicolson beat
Yulihan Luna by unanimous decision at
Adventist Health Arena in
Stockton, California, USA, on 13 December 2025, to win the
interim WBC female
super-bantamweight.
Nicolson vs. Turner Nicolson successfully defended her interim WBC super-bantamweight title by unanimous decision against Mariah Turner at
The Melbourne Pavilion in
Flemington, Victoria, Australia on 29 April 2026. ==Professional boxing record==