Nelson Khumbeni played for Norwich's Under-16s in their 1-0 win over Ipswich in the Hospital Cup (8th May 2018). He was then on the bench for Norwich City's under-18s in their 1-0 defeat to Reading on 18th August 2018. He is a pupil at the Langley School and was born in Malawi.

He is a member of Norwich's Under-18 squad for the 2019/20 season.

He signed a one year extension to his contract in July 2021.

He was released by Norwich on 20th May 2022. He had played three games in the Papa Johns trophy.

On 17th June 2022 it was reported that Nelson had signed a contract with Bolton Wanderers joining their newly formed B team. He said "Norwich has been a good place to develop and learn my craft and I'm looking forward to kicking on here at Bolton to grow as a person and grow as a player. Being at a place for so long, you maybe need a change of environment in order to improve and realise this is what you'd like to do. I came over here and loved everything I've seen. The stadium is amazing, the training ground is a good place to improve as a player and everyone has been welcoming. A lot of young players have had a chance here with the manager trusting them and putting a lot of faith in them. The team is trying to go onwards and upwards and it's probably the best time for me coming here."

He was loaned to AFC Fylde for the early part of the 2023/24 season, making nine appearances.

Nelson joined Morecambe on loan on 1st February 2024 until the end of the season. He made his debut on 3rd February against Crawley. He made a total of 19 appearances scoring once. On his return to Bolton. his contract was extended.

On 16th August 2024 he was loaned to Accington Stanley for the first half of the 2024/25 season having worked with Stanley's Assistant Manager Ged Brannon at Morecambe..