[5] On 4 June 2020, Niu made his NRL debut for the Brisbane Broncos, coming off the interchange bench in a record 59–0 home defeat against the Sydney Roosters.

Niu made a total of six appearances for Brisbane in the 2020 NRL season after suffering a season-ending wrist injury in round 10, as the club finished last on the table and claimed its first-ever wooden spoon.

[7] Niu played a total of ten games for Brisbane in the 2022 NRL season scoring three tries as the club finished 9th on the table and missed out on the finals.

[8] In the third group game at the 2021 Rugby League World Cup, Niu scored a hat-trick for Tonga in their 92–10 victory over the Cook Islands at the Riverside Stadium.

[10][11][12] In round 1 of the 2023 NRL season, Niu made his club debut for the Dolphins in their inaugural game in the national competition, defeating the Sydney Roosters 28–18 at Suncorp Stadium.

[15] Following the end of the 2024 NRL season Niu turned out for feeder club Norths Devils and won the Queensland Cup with a 34-20 grand final victory over the Redcliffe Dolphins.