Nelson joined
Leicester City's youth team at the age of 9. In the 2020–21 season, Nelson featured in a first-team squad during Leicester City's
UEFA Europa League campaign. He was named Academy Player of the Season at the end of the season. He was recalled from his loan on 6 January 2023. Later that month he joined
Doncaster Rovers on loan for the remainder of the season. In the
2023–24 season, Nelson was promoted to the first team. On 29 August 2023, he made his senior debut for Leicester as an 82nd-minute substitute for
James Justin in a 2–0 away win over
Tranmere Rovers in the Second Round of the
EFL Cup. On 8 December 2023, he signed a new contract until 2027. On 2 March 2024, he scored his first goal for the club in a 2–1 league defeat against
Queens Park Rangers. On 30 August 2024, Nelson signed for Championship side Oxford United on a season-long loan. On 5 November 2024, he
tore tendons in his quadriceps muscle during United's 1–0 win against
Hull City. ==International career==