Nicholas is the poor young scholar who rents a room in John's house. He sets his sights on Alisoun and fairly quickly manages to get her into bed. Nicholas is the mover and shaker behind most of the action in the tale: it's he who seduces Alisoun and tricks John into sleeping in a tub so he can spend the night with her. Nicholas takes a hot poker to the butt when his rival Absalom shows up at Alisoun's window intent on revenge. Based on Nicholas's prior behavior, it's tempting to say he had it coming.
Given his sexual prowess, we'd expect Nicholas to be a macho guy. After all, other characters in the Tales whom we suspect of being womanizers, like the Monk or the Nun's Priest, are burly Arnold Schwarzenegger types. But surprisingly, Nicholas's portrait actually makes him seem kind of feminine. He is "like a mayden meke for to see" (94) and "as sweete as is the roote / Of lycorys" (98-99). Some people think that the feminizing of Nicholas culminates in the scene in which he gets branded by a hot poker. Think about it: you have a phallic (penis-shaped) object invading a very suggestive region of Nicholas's body. Is it too much of a stretch to see some gender-bending going on here?
As a scholar, Nicholas has branched out from history, literature, and theology – or so-called "art" (83) – to study astrology, or fortune-telling. In fact, we learn that all Nicholas's "fantasye," or desire, is directed toward being able to make predictions about the future. Apparently he has already had some success predicting the weather, and perhaps it's John's knowledge of Nicholas's reputation as a fortune-teller that leads him to believe without question his prophesy of an impending flood. But Nicholas's desire to know the future is a form of hubris (pride): by desiring this knowledge he's taking upon himself powers that should belong only to God. This trait coincides with Nicholas's position as the tale's "command giver": in demanding Alisoun's body and John's obedience, he makes himself into a God figure. What, then, are we to make of the tale's ending, in which the once alpha Nicholas finds himself at the receiving end of a hot poker?