When first met, Nick seems charming and affable, but it soon becomes apparent that he has a drug habit, indulging in various kinds of drugs and urging Veronica and her friends to do the same. He takes a shine to the Pussycats and Cheryl Blossom, but at a party that he has with them, Veronica, Betty, and Archie, he peer-pressures several of them into having drugs with him, and after the party ends he makes unwanted advances on Veronica. Despite her insistence that she is with Archie, Nick pushes, and becomes angry when Veronica demands that he stops. In this moment, Nick's true character is revealed as he complains that Veronica always flirted and teased but then never indulged him. He then venomously threatens to sabotage her father's planned business deal with his father if she does not indulge him.
Later at a party being held in celebration of the Lodge's business venture, Nick approaches Veronica pretending to be repentant, but then spikes Cheryl Blossom's drink and takes her off to his hotel room when the drug starts to take effect. Fortunately, Veronica and the other Pussycats see this, and, correctly guessing Nick's intentions, pursue. They break into the hotel room right before he can date-rape Cheryl, and kick him into submission. Nick is then taken into custody.
Later, when being blackmailed by The Black Hood into giving him the name of a guilty person to kill in lieu of her family, Betty (with some reluctance), names Nick St. Clair.
- Nick represents the second villain in Riverdale who initially appears an affable and charming young man with an interest in Veronica Lodge who is then revealed to be a toxic misogynist who later only pretends to be sorry for previous bad behavior. The first was Chuck Clayton.