LEGO is a building block toy that thrives on its flexibility. The idea of people building whatever they want with LEGO bricks is a well-worn piece of its marketing, extending into media such as The LEGO Movie and Fox's reality competition series LEGO Masters. However, the brand is also known for being able to represent almost any other popular culture icon: Star Wars, Harry Potter, Jurassic Park, and so on. Nintendo got in on the action with LEGO Super Mario sets released for the character's 35th anniversary, and alongside those came the LEGO NES.
Based on the Nintendo Entertainment System that released in 1985 (after coming out two-years prior as the Famicom in Japan), LEGO's NES console came with additional pieces to build a controller, Super Mario Bros. cartridge, and an interactive television set that scrolls through a simplified level from the game. It also contained Easter eggs of its own, with the LEGO console hiding a recreation of the warp pipes from Super Mario Bros. World 1-2. This care would be great to see with some of Nintendo's other consoles, especially as it seems the LEGO Super Mario crossover will continue to expand.
Home Consoles
The Super Famicom/NES has some of the most iconic games in Nintendo's library: Super Mario World, The Legend of Zelda: A Link to the Past, and Super Metroid among them. However, the console's chassis is not too dissimilar from the NES. Thus, the Nintendo 64 would likely be the next most-interesting LEGO set as far as building potential. Its cartridge could be jutting out from the top of the console, and its three-pronged controller would be an interesting challenge.
Conversely, the GameCube wouldn't be much of a challenge to build at all, even if its controller is a fan-favorite for games like Super Smash Bros. The Wii is more deserving of a LEGO set given its status as one of the best-selling consoles of all time. It may not be possible to include the system's disks as a buildable component, but the Wii Remote and Nunchuk connected by a fabric LEGO string could be a fun nod to the console.
In terms of the company's modern systems, the Switch would be an obvious choice too. Not only has it vastly outsold the Wii U, approaching the Wii in that regard, but its design and the gimmick of being able to remove Joy Cons would also translate well to snap-together LEGO pieces. It's also more colorful, especially taking the newly announced Switch OLED model into consideration.
Handheld Consoles
Much like the NES console serves as a token of Nintendo's history, deserving of the LEGO treatment, so too does the original Game Boy model. Its chunky design and green-tinted screen are immediately recognizable. One idea it could attempt to be less of a "simple" set is including multiple game cartridges that could snap into the set and display their game through the screen like the LEGO NES television.
As fun as it would be to see more obscure devices like the Virtual Boy grace toy store shelves again in the form of LEGO sets, the next most likely candidate is the DS family of systems. Be it one of the many original DS models or devices like the 3DS and New 3DS XL, these firmly established Nintendo as the leading developer for the handheld market around the Wii era. All of these would also come with the obvious build challenge of including hinges that allow them to close.
Nintendo has a long history of handhelds prior to the DS, of course. Given Game and Watch models have released for Mario and Zelda's anniversaries, it might make sense for a LEGO variant to follow. The Game Boy Advance and its alternate models, the SP and Micro, are also contenders but admittedly don't have as many obvious draws to becoming LEGO sets. Regardless, it would be fun to see all of Nintendo's consoles come into the LEGO sphere, whether or not they have an interesting buildable "gimmick."