To be honest, this is stupid because a nihilist would get their wish and you'd go to prison and fuck up your own life? The only person that would kill a nihilist is basically just another nihilist.

Are they talking about the nihilism that is used as common parlence (the lack of belief in meaning) or the nihilism that is used to describe the philosophical ideology (the lack of belief in objective meaning)?

The two obviously aren't the same, the first is an untermenschen (underman, subhuman), a libertine like Cassanova, Stirner, or DeSade, with no regard for purpose at all besides satisfying their own base animal instincts, who make beasts of the themselves, rejecting their humanity and human minds. These are slaves, trapped in the illusion of their own freedom, when they have actually just destroyed their selves.

The second is an ubermenschen (overman, superhuman), who has suffered the tearing away of illusions such as those of religion, but has gained strength from the experience, he has embraced a subjective purpose greater than himself, it may apply to everyone, it may only apply to a few, or it ay only apply to him alone, but it only needs to apply to himself to drive him forward. This and his morality are real, and they truly are his own. Examples are neitzsche, camus, and sartre.

Those who remain in the illusion, willing or not, are the uplickmen (publicmen, or common people), they adhere to a slave morality that is not truly theirs but imposed upon them by some master who has trapped them in the bonds of illusions. There is little to say about them except they have little confidence in themselves, they in fact fear themselves, and so they destroy themselves in the same way the subhuman does, rejecting their own minds.

To be a superhuman is to be a philosopher and a scientist, to take sense and reason and make a personal religion out of it, from the study of the very theory of evolution that laid waste to God, and from the knowledge of oneself and one's own nature, can purpose and morality be drawn.

From that, which provides goals, priorities, and restrictions on reaching them, and from the study of men, and how they react to different measures of governance, can political ideology be determined.

Even the atheist can live a happy and fulfilling life, not only free to be good, but free to learn what being good entails, and why this is so.

How to keep demons away.