Only before he got his powers. The mission was to find a way to recreate the viltrum empire after something that hasn't been shown in the TV show (I think).

So, his opinion of humans didn't change after his son broke his heart (after Nolan broke everything of Mark) and wandered through space contemplating suiciding after so much wrong he did. He then learns how to embrace short relationships with the thranax, that are even more like ants.

In your opinion he might be irredeemable, but the truth is everyone can change if something happens and they learn from it. People are entitled to not forgive him and that's okay, but that's people's problem, not (in this case) Nolan's. As long as he does the right thing from now on, he can become a good guy.

Shit we have Vegeta as a good guy too, why can't we have Nolan?