Idk if they're the pioneer la but there's a mamak that's become quite a tourist spot (used to be a makan hunter spot for years) in KL, near Masjid Jamek, if you want to try other known places :D it's called Mansion Tea Stall, next to the Klang River side.
There’s also some hidden nasi minyak lauk spot upstairs inside the apartment that my ex colleagues like to visit (the apartment is a bit of a slum, remember when it got locked down during the pandemic).
Edit: I don’t quite remember if it’s nasi minyak or some other type of nasi