Do Nascimento set an aggressive pace and had a two-minute lead at the halfway mark of the men's race but he collapsed after mile 20, stunning onlookers as New York City Police Department officers ran to assist him. Organisers did not immediately respond to request for comment on his condition.
Chebet, who won in Boston this year, had accelerated around mile 15 and out in a final surge to cross the finish in two hours eight minutes and 41 seconds.
Ethiopian Shura Kitata (26) finished second in 2:08:54 and Dutchman Abdi Nageeye (33) took third.
Making her marathon debut, Lokedi hung in with the leading pack before pulling away in the final stages to win in 2:23:23.
Israeli Lonah Chemtai Salpeter (33) finished second in 2:23:30 and world champion Gotytom Gebreslase (27) of Ethiopia took third.
"I'm out of words, I'm really excited," said Lokedi, the eighth competitor to win the New York race in a marathon debut. "I'm just so happy that I did it here."
She said she had no expectations that she would win the race and would consult her coach before deciding on another marathon.
"I just wanted go and put myself in it and see where I'll end up," she told reporters. "Halfway through I felt really good."
The year's final marathon major was back at full capacity for the first time since the COVID-19 pandemic, with some 50,000 competitors hitting the streets and thousands of people congregating along the course to cheer.
The normally crisp and mild New York autumn conditions were replaced by heat hovering around 72 degrees Fahrenheit (22.2 Celsius), among the hottest conditions in the race's history.
Swiss Marcel Hug (36) had no issues collecting a New York record-tying fifth men's wheelchair title, establishing a nearly two-minute lead by the 25-kilometre mark before breaking the tape in a course record 1:25:26 to take his fifth major title of 2022.
American Susannah Scaroni (31) produced the fastest-ever time through the five boroughs on the women's side, winning her second wheelchair major in 1:42:43.
