Nick was 22 in 2002, yes. At that time, he was working on releasing and promoting his solo album. The Boys themselves were on hiatus. The most recent BSB song at that time would have been "Drowning" (released October 2001). Nick's first single was "Help Me" from "Now or Never" and that's what people would've known him for in that time period. Once the album itself didn't do as well as Justin Timberlake's CD (which would've been the big fan drama and Nick's career obsession at the time, by the way, was the comparison between the two), he kind of sunk out of major media headlines, but the next two singles - "Do I Have to Cry For You" and "I Got You" - did sort of okay. You'd have to look up numbers to see how "ok" or "not ok" they did. I know Help Me was the most successful of Nick's solo singles, though.
There ya go... a BSB history lesson in a nutshell.