Nathan Wournos and Duke Crocker used to have a very difficult relationship that eventually became friendship over the years. They first didn't like and trust another, but eventually worked together with Audrey Parker to help the Troubled. Fans of Haven, who ship the two together dub the pairing "Nuke".
Nathan and Duke grew up in Haven, Maine together and Duke was present both times Nathan's trouble activated. When both were children, Nathan broke his arm while sledding and couldn't feel it. Duke was the one who brought Nathan to the hospital, then went back to sledding. While they were in school together, Duke bullied Nathan; one time Duke convinced Nathan that Carla Rose liked him and all Duke's friend's "congratulated" Nathan. The boys used the "clap on the back" motion to stick push pins in Nathan's back. Because Nathan couldn't feel it, he went to her with blood all over his back.
Years later Duke returns to Haven after a long absence and invites Nathan out on a fishing trip under the premise of friendship. Nathan soon discovers that Duke was using him and his police officer status to smuggle something in. Making Nathan his alibi and cover when the coast guard showed up. Nathan was furious and fought with Duke for an hour and it reactivated his trouble.
At some point, when Nathan is having problems starting out as a cop, he considers quitting and tells Duke this when they are playing pool. Duke secretly later help Nathan get Nick McGinnis, which helped Nathan with his career and convinced Nathan to stay.
In Welcome to Haven, when Duke's revoler is found at the scene, Nathan automatically assumes Duke is involved in the murder and takes Agent Audrey Parker to Duke's boat. He tells her that Duke is basically a "pain in the ass". Nathan later arrests Duke, but he is innocent of the crime. In Harmony, Nathan catches Duke walking out of the building and the two bicker. When Nathan is influenced by a trouble, he comes after Duke and attacks him.
In Ball and Chain, Nathan helps Duke when Duke begins to rapidly age. While they wait outside the lighthouse, Duke asks Nathan if he hates Duke. Duke also mentions he doesn't want to die alone, and Nathan assures Duke that he won't die, and Nathan jokes that he would be the one to kill Duke. When Duke stops breathing, Nathan gives Duke CPR.
In A Tale of Two Audreys, Duke helps Nathan out when a trouble takes on the biblical plagues and begins killing first born sons, like Nathan.
In 301, Duke tries to convince Nathan that he had nothing to do with Audrey's disappearance. Nathan doesn't believe him and attacks. They are forced to stop when a trouble hits and begin to look for Audrey.
In Fallout, Duke looks for Nathan after coming out of the Barn and Nathan is happy to see Duke alive.