Nintendo has kept its promise and is bringing back the NES Classic Edition Re-stock after a short period of discontinuation.
As Nintendo itself puts it: "The classic NES is back in a familiar-yet-new form as a mini replica of Nintendo's original home console".
When the console first hit the market back in November 2016, there was a great demand, leading to the sell-out of the entire stock nearly immediately. The micro-console was then discontinued in early 2017, much to the dismay of many fans. NES Classic Edition will now return with full-on availability. The mini-console became sparse in retail stores as soon as it launched. Furthermore, Nintendo explains that both the NES Classic and its successor the SNES Classic "are expected to be available through the end of the year".
You may also see it called the "Nintendo NES Classic Edition" or just "NES Mini", but they're all the same thing. Tracking down a Nintendo and purchasing all the games that were included in the NES Classic would cost hundreds of dollars.
Currently, no release date for the SNES Classic second launch has been announced. Nintendo also released Star Fox 2, a previously unreleased video game, bundled with the game library of the Super Nes Classic.