[7] Nelson made his professional debut for Toronto FC II in USL League One on April 6, 2019, coming on as a substitute against Orlando City B.

[23] On January 24, 2025, Nelson returned to Canada, signing with Major League Soccer side Vancouver Whitecaps FC.

[25] Nelson made his debut for the Canada national under-15 team in the 2017 CONCACAF Boys' Under-15 Championship on August 13, 2017, against the United States.

[26] Nelson scored twice more in the tournament – against Curaçao and Costa Rica respectively – as Canada qualified for the FIFA Under-17 World Cup for the first time since 2013.

[28][29] Nelson was named to the Canadian U-23 provisional roster for the 2020 CONCACAF Men's Olympic Qualifying Championship on February 26, 2020.

[35] Initially left off the roster, on June 26 he was called into the final squad along with Liam Fraser as replacements for Sam Adekugbe and Stephen Eustáquio.