I was recently playing on a friend's NES Classic, and noticed that the controller ports look similar to the ones on a Wii remote (where you can plug in the Numchuck or Class Controller). Keep in mind that these ports work with original NES controllers, so this wasn't Nintendo reusing its designs (at least not that design specifically). Upon plugging in a Class Controller (Wii Classic Controller, designed for the Wii controller), I was surprised to see that it actually worked, and thought it was an authentic NES controller. Now, I don't have an original NES to test this on, but are the controller ports from the original NES identical to the ones on the Wii remote?
The two consoles do have different controller ports. The NES Classic Edition is not directly compatible with original NES controllers, but it does work with the Wii Classic Controller.
The original NES uses a 7-pin connector:
The NES Classic Edition does not: