The ESRB, the organisation behind age ratings for games, was noted recently to have age-rated a previously unknown game called Nintendo World Championships: NES Edition. Often, age ratings usually follow rumours and leaks, but this is the first time the title has reached the public, and we therefore do not know more than what the ESRB writes on its website.
The ratings summary reads: "This is a collection of 2D challenges and platformer games in which players traverse through various modes (eg, speedrun, survival). Several challenges involve reaching specific points, while others prompt players to defeat small enemies or survive brief battles. Some games depict pixelated characters using small swords or arrows to strike at enemies; enemies typically get stunned or disappear in a flash."
The description sounds similar to the specially made cartridge used in the 1990 American Nintendo World Championships, which contained mini-games based on Super Mario Bros., Rad Racer and Tetris, among others; but also the 2013 NES Remix for Wii U and 3DS which boasted challenges and competitions based on a number of NES games.
An official announcement is likely not too far off, and it's possible it will be one of Nintendo's as-yet-unrevealed titles for 2024. Keep your eyes and ears open.