I still can't help thinking of Nadakhan as a sad figure, someone whose story fits more in some ancient poem about a lost civilization that died and collapsed. I know him being obsessed with Nya isn't good, but they don't actually add that detail until like episode 4 or 5 of his season. If you just skip episodes 5 to 10 (as I did), you get a way better story of a man who's lost everything and simply wants to watch the worlds burn. If he can't have Djinjago back, he wants the world to suffer as he has.
And I can't blame him. Imagine you came from an ancient civilization. You had everything as the prince and heir to the throne. But you chafed under the pressure and wanted to explore the worlds. You escaped your home, got yourself exiled, wind up in exile. That's Nadakhan's story. He had Delara and his crew and his piracy to stave away the loneliness, but then he was locked in his lamp for centuries.
When he awakens, he finds his partner is dead. His kingdom is gone. He's the last of his kind, because the mortals have foolishly exterminated his entire race. He has no home. No home. He is lost in the world, a man utterly broken. And he will see the people that took everything from him pay. He will have his revenge. And I almost can't blame him. There's something so sad about that story to me, and there is an emotional depth to Scott McNeil's performance. Very cruel, capable of grief and sadness (he did seem genuinely hurt knowing Delara was dead and Djinjago was too). He's a Djinn who already had few morals, but who's also lost his sanity with the loss of his family.