From 2010 to 2012, Mata'utia played for the Newcastle Knights' NYC team. On 21 April 2012, he played for the New South Wales Under-20s team against the Queensland Under-20s team and scored a try. In 2013, he moved on to the Knights' New South Wales Cup team. On 16 October 2013, he re-signed with the Knights on a 1-year contract, later extending it by another year in 2014. On 9 July 2014, he played for the New South Wales Residents against the Queensland Residents and scored two tries.
2014
In Round 20 of the 2014 NRL season, Mata'utia made his NRL debut for the Knights against the Sydney Roosters, alongside his brother Sione Mata'utia who also debuted for the Knights in the same game. This was the first time since Round 1 of the 1942 NSWRFL season, that two brothers had debuted in the same game together, Bill and Doug McRitchie debuting for the St. George Dragons on that day. On 9 September 2014, he was named in the Samoa train-on squad for the 2014 Four Nations, but didn't make the final 24-man squad. Late in September 2014, he signed a letter of intent to join the Canterbury-Bankstown Bulldogs on a 4-year contract starting in 2016, along with his brothers Sione and Pat. However, the NRL's rules didn't allow the Bulldogs to register the contracts until 30 June 2015, leaving the option of staying at the Knights open for the Mata'utias.
2015
On 19 March, Mata'utia re-signed with the Knights on a 3-year contract, along with his brothers Sione and Pat. In May, he again played for the New South Wales Residents against the Queensland Residents and scored two tries, this time alongside his brother Peter. Chanel managed to play only 1 NRL game in the 2015 season.
2016
After impressing the new coaching staff in pre-season, Mata'utia was selected to play in the Knights' round 1 side against the Gold Coast Titans, though he was injured during the game. Multiple injuries throughout the year meant the round 1 match would be his only NRL match for the season.
2017
After another injury plagued season, Mata'utia was able to break back into the Knights' NRL side in round 18 of the 2017 season, going on to play 4 NRL matches for the year and scoring two tries. On 23 November, it was announced that he would be retiring from the professional level of the game and joining the local Newcastle Rugby League, after being granted a release from the final year of the Knights contract. Mata'utia said after being released “The club has been great to me and I will miss everyone, but it is the right time for me to step away from the game at this level”.
