On the December 17, 2020 episode of NXT UK, it was announced that Ben Carter had signed with WWE and would be making his debut on NXT UK. Carter made his debut on the January 7, 2021 episode, failing to win the NXT Cruiserweight Championship from Jordan Devlin. After wins over Sam Gradwell and Josh Morrell, Carter announced on the March 11 episode of NXT UK that he would be wrestling under the name Nathan Frazer.
Frazer teamed with Jack Starz on the June 3 episode of NXT UK, failing to take the NXT UK Tag Team Championship from Pretty Deadly (Lewis Howley and Sam Stoker). Frazer would go on to compete in a number one contendership tournament for the NXT UK Heritage Cup, but was eliminated by Teoman in the first round, before failing to win a triple threat match for an NXT UK Championship opportunity. On the January 13, 2022 episode of NXT UK, Frazer failed to defeat Walter in the latter's final NXT UK match. Frazer would have his final match in NXT UK on March 3, where he was defeated by NXT UK Champion Ilja Dragunov.
On the April 12 episode of NXT, Frazer announced that he would be making his debut for the brand, before defeating Grayson Waller at NXT Spring Breakin'. On the August 2 episode of NXT 2.0, Frazer responded to Carmelo Hayes' open challenge for the NXT North American Championship, but lost when Giovanni Vinci interfered.
On the June 13, 2023 episode of NXT, Frazer defeated Oro Mensah 2–1, who wrestled on behalf of Noam Dar due to Dar suffering an injury to become the NXT Heritage Cup winner. Frazer would lose the cup back to Dar 69 days later at NXT Heatwave. In late 2023, Frazer formed a tag team partnership with Axiom. In early 2024, the duo competed in the NXT Tag Team Championship eliminator tournament, defeating No Quarter Catch Crew (Charlie Dempsey and Myles Borne) in the first round and Latino World Order (Joaquin Wilde and Cruz Del Toro) and The O.C. (Luke Gallows and Karl Anderson) in a triple threat tag team match in the final to face NXT Tag Team Champions The Wolf Dogs (Baron Corbin and Bron Breakker) for the titles at NXT Stand and Deliver, but failed to win the match. In a rematch on the following episode of NXT, Frazer and Axiom defeated The Wolf Dogs to become the new NXT Tag Team Champions. After the match, The Final Testament's Authors of Pain returned to NXT and attacked Frazer and Axiom. During week two of Spring Breakin', Frazer and Axiom successfully defended their titles against AOP after interference from New Catch Republic (Pete Dunne and Tyler Bate). On the May 21 episode of NXT, Frazer and Axiom retained their titles against The D’Angelo Family (Luca Crusafino and Channing “Stacks” Lorenzo). After the match, they were attacked by The O.C. (Luke Gallows and Karl Anderson). At NXT Battleground, Frazer and Axiom retained their titles against The O.C. On the June 25 episode of NXT, Frazer failed to defeat Tony D'Angelo for the NXT Heritage Cup. On the following day's episode of WWE Speed, he defeated Akira Tozawa to advance in the Speed Championship number one contender's tournament, but lost to The New Day's Xavier Woods in the final the next week. After multiple successful title defenses, on the August 13 episode of NXT, Chase University's Andre Chase and Ridge Holland defeated Frazer and Axiom for the NXT Tag Team Championships, ending their reign at 126 days. The pair regained the titles in a rematch nineteen days later at NXT No Mercy to become two-time champions.