He trusted the cube too much to an unhealthy degree, his fate was decided as soon as he came to know about the flood, either he could have thrown the cube away and then lost everything with it or he could take that one last gamble to fix everything.
Did he know that that he was gonna get betrayed by the cube again? Probably
Did he have any choice but to trust the cube? Probably not
Now at this point you expect Nox to be fueled by despair and commit these atrocities like a stereotypical vilain but the thing is, despair is not what fuels him, Nox is fueled by guilt and hope.
Now whether Nox has good intentions or not doesn't really matter because at that precise moment where he lost his family to the flood he has no choice but to try to get them back, even if deep down he knew that he was going to get fucked over by the cube, that powerful last image that one last tear shows us that he knew all along that his plan was doomed to fail but that he had to choice than to follow this false ultimatum and keep trying because such is the nature of man.
Nox, as a character, did nothing wrong but the actions he commited were wrong.
Thus it can be argued that Nox both did everything wrong and nothing wrong.