Veteran striker Stewart had announced this would be the last of nearly 800 first-team appearances and he stepped off the bench in the 66th minute to face the club where he first made his name. Both sets of fans stayed behind at the end to cheer Stewart off the pitch.
He said: "It was unbelievable that the Roves supporters did that, despite their disappointment at losing. I never expected it and it brought a lump to my throat."
Stewart touched on Ryan Harley's 78th-minute cross for fellow substitute Nardiello to open the scoring with a close-range shot and Exeter's dominance was rewarded when Harley put Nardiello through in injury time to round goalkeeper Conrad Logan and slide home the second.
Exeter coach Rob Edwards paid tribute to Stewart, saying: "I first came across Marcus nearly 20 years ago when I arrived to play for Bristol City and he was the main man at Rovers.
"Marcus was a very special player then and he has gone on to have a wonderful career. This was his day and I'm delighted we were able to mark it with a win."
Source: PA
Source: PA