Ok, lets clear the confusion (hopefully)
CastleVania Chronicles is a re-release of Akumajou Dracula X68000, containing the original and an updated version, all performed through emulation. Akumajou Dracula X68000 is, basically, a remake of the original CastleVania, not neccesarily a port with updated graphics, but more-so of a retelling. Basically, X68000, and vicariously Chronicles, is related to the NES CastleVania as Super CastleVania IV is.