Osika achieved her first national top-three finish in the 1500 m at the 2018 USA Indoor Track and Field Championships, behind Shelby Houlihan and Colleen Quigley.[10] Although the United States could only send two athletes to compete at the 2018 IAAF World Indoor Championships, Houlihan had initially stated she would only run the 3000 metres at the world championships, opening up a spot for Osika to run at her first track and field world championship.[10] However, Houlihan later decided to run in both events, blocking out Osika from the spot.[11] During the outdoor season, Osika was selected for the 2018 NACAC Championships team, where she won a silver medal in the 1500 m.[12]
On 11 February 2022, Osika was part of the Nike Union Athletics Club team that set an indoor world record in the distance medley relay, with a time of 10:39.91 at the Lilac Grand Prix.[5] The record was only briefly held, as it was overtaken by New Balance running 10:33 on 15 April later that year.[14]