In early 2018, the Swedish athlete made his debut in the IBU Cup in Osrblie, though he primarily participated in Junior World Championships until 2019.

In March 2022, Nykvist achieved his first IBU Cup podium finish, securing third place in a mixed relay in Ridnaun alongside Ingela Andersson, Elisabeth Högberg, and Henning Sjökvist.

At the beginning of the 2023/24 season, Nykvist delivered strong performances in the IBU Cup, achieving two top-10 results and a podium finish in the mixed relay.

[5][6] This earned him World Cup starts in December and January, where he narrowly missed the podium with the Swedish men's relay team in Oberhof.

Despite these performances, he was dropped from the national team at the end of January 2024 and returned to the IBU Cup and European Championships, where he finished outside the top 30.