Nidoking is definitely a dino type pokemon. I know he starts off lookin like a rabbit with those big ears and whiskers much like Ratatta did sort of as well. But this is mostly because back then Nintendo's designs of the first gen were sort of limited due to pixels and so lots of pokemon ended up slightly resembling each other. This is sort of the case with Nidoran and Ratatta as well as other similarities in other species.

Anyhoo he is a very badass poison type and is right up there with Tyranitar and Rhydon. :D I love large dino-dragonlike pokemon.