Nezir gained his first international experience in 2021, when he won the bronze medal in the 400 metres in 49.05 seconds at the U20 Balkan Indoor Championships in Sofia and won the gold medal with the Turkish 4 × 400 m relay team in 3:18.11. He then won the relay again in 3:13.70 at the 2021 Balkan Athletics Indoor Championships in Istanbul.[4] In July, he competed in the 400 metres hurdles at the 2021 European Athletics U20 Championships and was eliminated in the semi-finals with a time of 51.51 seconds.[1]
In July, Nezir began his outdoor 2022 season with a seventh-place hurdles finish at the 2022 Mediterranean Games in Oran in 50.09 seconds.[9] He won the bronze medal in the relay in 3:04.55, behind Algeria and Italy. Later that month he won the 2022 Balkan U20 Athletics Championships in Denizli in 50.86 seconds, followed by his most significant win yet – a gold medal at the World U20 Championships in 48.84 seconds.[1] The time was also a Turkish under-20 record, and Nezir was congratulated by the mayor of Buca after his return home.[2]
In 2022, Nezir became the Turkish champion in the 400 metres as well as over 400 metres hurdles. He was also the 2022 Turkish Indoor Athletics Championships champion.[1]
