Nikolchenko commenced her 2018 senior season at the LA Lights International Tournament in Los Angeles.

She also competed at the Miss Valentine Tournament in Tartu, Estonia, where she won the all-around, hoop, ball and clubs finals and finished 4th in ribbon.

[9] She also took part in the Holon Grand Prix, where she also placed 5th in all-around and won the silver medal for hoop and clubs.

Nikolchenko finished her 2018 season at the Grand Prix Final in Marbella, where she won the all-around gold.

[12] At the Grand Prix in Marbella, Nikolchenko finished 4th in the all-around, 3rd in hoop, 6th in ribbon, 7th in clubs and 8th in ball.

[15] Nikolchenko participated at the 2019 Tashkent World Cup, finishing 6th in the all-around after several mistakes in her ball routine.

[19] At the 2019 Cluj Napoca World Challenge Cup, Nikolchenko brought two new routines for ball and ribbon.

At the 2019 Rhythmic Gymnastics World Championships in Baku, she qualified for the ball, clubs and ribbon final.

In July 2021, she announced through her Instagram account that she was taking a break from gymnastics and would not attend the Olympic Games due to health issues after contracting COVID-19.

[20] In July 2023, Nikolchenko announced that she would be coming back to Ukraine after her stay in the United Arab Emirates.

[22] On November 23, 2023, Nikolchenko was expelled from Ukrainian Gymnastics Federation following racist comment posted about Poles via Instagram.