Coromon is only a ripoff in the same way that any scrolling platformer is a ripoff of Super Mario Bros. building off the basic chassis of existing games to make new ones is a practice as old as videogames itself and why genres exist. the difference is that Palworld is full to the brim with monsters that can be difficult to tell at a glance from existing Pokémon- look at this article's embedded image, that's just a Wooloo with horns on it's hind legs- whereas Coromon, Digimon, Dragon Quest Tamers, Yokoi Watch, Cassette Beasts, and anything else in the genre aren't ripoffs and are even available on Nintendo consoles

i know that's not the angle Nintendo is using in court, but it's certainly the reason why they're in court in the first place while ignoring the plethora of older games that would also clearly violate those patents