Early career Growing up in Orangeville, Ritchie competed with the Toronto Marlboros in the Greater Toronto Hockey League (GTHL) and with the
Ontario Junior Hockey League's (OJHL)
Georgetown Raiders. As a 15 year old, he scored 50 goals and 45 assists in 68 games to help the Marlboros compete for the OHL Cup. During the offseason, he was named to Team Ontario at the 2011 U16 Canada Winter Games. Ritchie gave up lacrosse in the summer of 2011 to focus completely on his hockey career. He was subsequently drafted second overall by the
Peterborough Petes in the 2011
Ontario Hockey League (OHL) draft. By December, Ritchie had collected 15 goals and 11 assists in 28 games and was named to the
CHL/NHL Top Prospects Game. As a result of his play, Ritchie was ranked seventh amongst North American skaters by the
NHL Central Scouting Bureau's mid-season list of
2014 NHL entry draft eligible players. On February 10, Ritchie was named OHL Player of the Week after he tied a franchise record by scoring five goals in one game against the
Kingston Frontenacs. After the Petes were eliminated from the
2014 OHL playoffs by the
Oshawa Generals, Ritchie was the recipient of the teams' Bill Bennett Award and Ed Rowe Memorial Award as the leading scorer and most goals winner. Ritchie was drafted in the first round, tenth overall, by the
Anaheim Ducks at the 2014 NHL entry draft. On August 2, 2014, the Ducks signed Ritchie to a three-year,
entry-level contract. After attending the Ducks 2014–15 training camp, Ritchie was reassigned to the OHL's Peterborough Petes for his final junior season. On January 7, 2015, Ritchie was traded by the
Peterborough Petes to the
Sault Ste. Marie Greyhounds, along with teammate Connor Boland, in exchange for Kyle Jenkins and four draft picks.
Anaheim Ducks After attending the Ducks 2014–15 training camp, Ritchie was reassigned to the OHL's Peterborough Petes for his final junior season. However, he was still re-assigned to the Ducks'
American Hockey League (AHL) affiliate, the
San Diego Gulls, to begin the season. After playing in 12 games, and recording 12 points, Ritchie ranked tied for third among AHL leaders in goals. As a result, he was recalled to the NHL level on November 14, 2015, alongside teammate
Michael Sgarbossa. Ritchie subsequently made his NHL debut on November 16, 2015, against the
Carolina Hurricanes, becoming the 11th youngest Duck to reach that milestone. He later recorded his first NHL point, an assist, on December 1, 2015, during a 4–0 win over the
Vancouver Canucks. As he continued to play with the Ducks well into the new year, Ritchie recorded his first career NHL goal on March 14, 2016, in a 7–1 win over the
New Jersey Devils. He later scored a tip-in goal to help the Ducks win the
Pacific Division title and qualify for the
2016 Stanley Cup playoffs. However, before he could make his postseason debut, he was re-assigned to the Gulls. At the time of his reassigned, Ritchie had amassed four points in 33 games for the Ducks during the regular season. The following season, Ritchie made his the Ducks' home opening night roster against the
Dallas Stars on October 13, 2016, where they fell 4-2. He spent the majority of the season playing on a line alongside center
Antoine Vermette and right wing
Corey Perry and ranked eighth in the NHL in hits by April. On April 6, Ritchie was suspended two games for roughing
Chicago Blackhawks defenceman
Michal Rozsíval, and had to miss the last game of the regular season against the
Los Angeles Kings. He returned to the lineup for the Ducks' first round playoff series against the
Calgary Flames. He scored in his second game back to spark a comeback in Game 3 of the Western Conference First Round sweep of the Calgary Flames. After sweeping the Flames in four games, the Ducks entered the second round against the
Edmonton Oilers. After committing a penalty during Game 1 of the series, Ritchie was scratched for Game 2 and had decreased ice time during Game 3. However, Ritchie scored the game winning goal in Game 7 to send the Ducks to the 2017 Western Conference Finals against the
Nashville Predators. During the series, Ritchie was ejected from Game 6 for
boarding Predators forward
Viktor Arvidsson. The Ducks ended up being eliminated that game and the Predators went on to the
2017 Stanley Cup Finals. On October 19, 2018, the Ducks signed Ritchie to a three-year, $4.6 million contract, ending his holdout. Ritchie missed the team's first seven games of the season.
Boston Bruins On February 24, 2020, Ritchie was dealt at the trade deadline to the
Boston Bruins in exchange for
Danton Heinen. At the time of the trade, he had recorded eight goals and 11 assists for 19 points in 41 games. Ritchie only played in seven games, where he recorded one goal and an assist, before the league paused due to the
COVID-19 pandemic. In a rebound season with the Bruins, he appeared in every game with the Bruins, collecting 15 goals and 26 points in 56 contests. He added 4 points in 11 playoff games before he was surprisingly released as a free agent by the Bruins after he was not tendered a qualifying offer as an impending restricted free agent.
Toronto Maple Leafs On July 31, 2021, Ritchie was signed to a two-year, $5 million contract with his childhood team, the
Toronto Maple Leafs. Ritchie was primarily signed to replace
Zach Hyman's role, who the Leafs lost to the
Edmonton Oilers during the same free agency period, and was expected to serve as a gritty, aggressive winger on the top line alongside
Auston Matthews. However, Ritchie struggled in his time with Toronto, failing to contribute offensively and not being able to keep up with the speed of his linemates; after starting the season in his expected role on the top line, Ritchie was gradually demoted until finally being placed on waivers on January 6, 2022. He cleared waivers the following day and was assigned to the Toronto Maple Leafs'
taxi squad. After the NHL eliminated the taxi squad following the NHL All Star break, Ritchie was assigned to the
Toronto Marlies, for which he appeared in two contests for, scoring one goal. Following waiving Ritchie, the team began to explore trade opportunities to give him another opportunity at playing in the NHL and to alleviate his burdensome cap hit.
Arizona Coyotes On February 19, 2022, Ritchie was traded to the
Arizona Coyotes along with a third-round pick in
2023 or a second-round pick in 2025 in exchange for
Ryan Dzingel and
Ilya Lyubushkin. During the
2022–23 season, having re-established himself in the league through his tenure with the Coyotes, he posted 21 points through 58 games.
Calgary Flames On March 3, 2023, Ritchie was dealt at the NHL trade deadline by the Coyotes, alongside
Troy Stecher to the
Calgary Flames in exchange for his older brother
Brett Ritchie and
Connor Mackey. It marked the first time in NHL history that brothers were traded directly for each other, but the second time overall in North American professional sports, following a 2008
National Basketball Association (NBA) trade that saw
Pau Gasol and
Marc Gasol traded for each other. Nick scored his first goal in his debut game with the Calgary Flames against the Dallas Stars on March 6. During the
2023–24 preseason, Ritchie signed a professional tryout offer with the
St. Louis Blues on September 14, but was released on September 29.
Oulun Kärpät On November 25, 2023, Ritchie signed a one-year contract with
SM-liiga club
Oulun Kärpät. On December 29, Ritchie was handed an eight-game suspension after he had punched
HC TPS player
Markus Nurmi to the head multiple times while he was lying on the ice. On January 29, 2024, Kärpät announced that they had terminated Ritchie's contract.
Iserlohn Roosters On January 29, 2024, the
Iserlohn Roosters of the
Deutsche Eishockey Liga (DEL) announced that they had signed Ritchie.
Slovak Extraliga On October 24, 2024, Ritchie signed with
HC Nové Zámky of the
Slovak Extraliga. While there, he played two games against his brother, Brett, who played for
HK Nitra. After recording 24 points in 19 games for Nové Zámky, Ritchie transferred within the league to
HC Slovan Bratislava on January 31, 2025.
Erste Liga On December 11, 2025, Ritchie signed with
HSC Csíkszereda of the
Erste Liga for the remainder of the season. ==International career==