Nintendo published Pokémon Pokopia alongside The Pokémon Company.
Nintendo’s publishing role fits the game’s status as a Nintendo Switch 2 release. The company is one of the principal owners of the Pokémon brand and regularly publishes Pokémon games for its hardware platforms.
The Pokémon Company was also credited as a publisher. It manages and promotes the Pokémon brand across games, merchandise, animation, and other media. Listing both Nintendo and The Pokémon Company reflects the shared publishing structure used for many major Pokémon releases.
Game Freak and Omega Force are different: they are the developers credited with making Pokopia. Koei Tecmo is the parent company associated with Omega Force, but it is not the answer to this publishing question. Keeping publisher and developer roles separate helps avoid one of the most common factual mix-ups about the game’s credits.