Champ Hardy is a recurring character in Season 1 of Wynonna Earp.
Champ picked on girls as a kid until Waverly Earp kicked him in the nuts. Their relationship must have changed at some point because according to Wynonna, Champ and Waverly were highschool sweethearts. Champ is a former rodeo star and now works as a ranch hand and handyman for hire.
They breakup in the episode Constant Cravings because of his constant cheating and mistreatment of her.
Champ dislikes Nicole either because he is a homophobe or because he's jealous of her relationship with Waverly. Or because of both.