The American backed up his short program win with another triumph on Friday (16 April) at the World Team Trophy event in Osaka, Japan, the three-time world champion beating two-time Olympic winner Hanyu Yuzuru in the men's free skate, the two scoring 203.24 and 193.76, respectively.
Capping a resurgent season himself, Russia's Mikhail Kolyada finished in third at 180.72. Kevin Aymoz of France was fourth (169.13).
Chen hit four quadruple jumps in his program, set to Philip Glass, only one minor mistake committed in combination. Hanyu, meanwhile popped an attempted quad Salchow near the start of his otherwise chilling free skate.
Chen backs his win up at worlds last month, ending a stop-and-start season with wins at Skate America, the U.S. Championships, worlds and now World Team Trophy.
WTT is a team event happens every two years since its inception in 2009, and - with just the ladies' and pairs' free skates to go - Russia looks primed to win its first-ever title at it. They lead with a score of 91, followed by the U.S. (83) and Japan (78).
Chen-pion again: Nathan hits four quads in win
While neither Chen nor Hanyu were at their ultimate best, it was the popped Salchow that made much of the difference on Friday, Hanyu clearly knowing he had left the door ajar for Chen, who skated last.
The American, who needed a come-from-behind win at worlds in Stockholm last month, was solid across his jumping passes, hitting a quad flip to start, then triple Axel-double toe in combination, triple Lutz, quad Salchow, quad toe-Euler-single flip in combo, quad toe-triple toe and triple Axel.
The popped flip did not prove too costly.
"Just to have the opportunity to come here, I’m so truly grateful for," Chen said after his win. "After worlds were cancelled last year, to be able to have a competition truly means a lot as an athlete - to be able to perform, to be able to compete in front of people. I’m truly grateful."
Chen outscored Hanyu by less than a point (95.40 to 94.50) in program components (artistry), as well, both men receiving nines across the board for their artistic presentation.
"I had a little bit of a mistake in the short and I had a big mistake in the Salchow in the free. I need to train more," an honest Hanyu said in Japanese. "After the world championships I didn’t feel great to be honest. There was stress, fatigue - I had a bad stomach. The mistake today was unfortunate but I stuck to the program and I’m satisfied with that."
"I’m a bit disappointed I couldn’t do the quadruple Axel this season but I learned a lot by trying it. Next season, I’m looking forward to landing the quadruple Axel to complete my performance." - Hanyu Yuzuru
Chen and Hanyu head into the Olympic season ahead of Beijing 2022 as the top duo in men's skating, with the likes of world silver medallist Kagiyama Yuma (who didn't compete here), Kolyada, Aymoz and others chasing them.
Chen added: "I’ll take it competition by competition (for next season). There’s still a whole season ahead of the Olympics. I’m going to rest, recover and get myself refreshed for the following season."
Men's field: Kolyada finishes strong, Brown struggles
The final competition of the figure skating season provided a strong final chapter for Kolyada, the former world bronze medallist who missed the entirety of the 2019-20 season due to illness and injury.
He faded towards the end of his "White Crow" free skate - with a double Axel and double loop - but new coach Alexei Mishin held his arm up as he left the ice, a clear sign of victory after what has been a challenging time.
He'll challenge, no doubt, for the podium at the Winter Games next February.
"Every competition counts and is important to me, but what’s important about this WTT is that it’s being held in Japan - with a crowd," Kolyada said in a nod to the limited amount of spectators watching. "It’s nice to be able to finish here what I consider has been a good season for me."
After a chilling short program where he was third, American Jason Brown struggled in his free skate, called for an under-rotation on his quad Salchow and popping a triple Axel. He fell on his final triple Lutz.
While Aymoz was fifth, Russian youngster Evgeni Semenenko was fifth, Olympic silver medallist Uno Shoma sixth and Italy's Daniel Grassl seventh.
Tearful Uno Shoma: 'I feel terrible'
It was a frustrating and disappointing two days of skating for Uno, who had recently changed his boots (a big change in skating) and said he had a "poor build-up" into World Team Trophy.
He was sixth in the free having been ninth in the short.
"I’m not in the greatest condition," he told reporters in Japanese. "I shouldn’t - can’t - have as poor of a build-up as I did for this competition."
"I’m grateful to my teammates for the support and feel terrible for the performance I had." - Uno Shoma
He added: "It’s embarrassing, but all I can do is support my team now. ... I was happy with where I was at the worlds and was planning to end my season there. But I’m here and as long as I’m here, I have to be competitive, not just turn up."
Hanyu said he dedicated his free skate in part to Uno: "I saw a teammate not be able to perform like he wanted to. I felt compelled to skate for him and that gave me strength different to what I’m accustomed to."