It definitely is overplayed, if you can ever consider a classical piece overplayed these days....

That said, it's beauty and depth is unmistakable, even though Chopin only wrote it as an exercise for his sister. In some ways it is the quintessential Chopin piece, and it has such an emotional - but not sad - melancholy about it that is so characteristic of him. There are definitely more complex and overall better nocturnes, but it is still a great piece.