That was a large part of it.
Nintendo also didn't try to oversell the systems capabilities or the games, which was a big problem with the marketing materials for older games and game systems.
They also limited 3rd party companies ability to make games for the system (https://en.wikipedia.org/wiki/CIC_(Nintendo)#10NES) to ensure a certain degree of quality. That's also the origin of the gold Nintendo Seal.
The NES also had Super Mario Bros as a launch title in the US and that game holds up incredibly well to this day. It was truly a big leap in video game design, especially considering games like Ms Pacman and Donkey Kong Jr. were winning Best Game awards in magazines the year before the NES launched.
Lastly, the Light Gun and Duck Hunt were also big system sellers. As far as I know, no other console had an experience like that and much like the Wii and the DS, gimmicks like that are very popular among people who don't play a lot of traditional video games.
You should also consider the velocity that Nintendo launched into the console industry with. A year after the NES came out, The Legend of Zelda came out which was another giant leap in game design and the first home console game to allow you to save your progress. Two years after that Super Mario Bros. 3 came out which was an absolutely massive leap over the first Super Mario Bros. A year after that they launch the GameBoy and suddenly you can play Super Mario Land on the go.
Nintendo was responsible for a lot of innovation in a very short amount of time.