It is believed that unlimited power corrupts and corrupts the ruler of the state. Is this opinion confirmed by the example of Nero?

Yes, it does. Nero possessed practically unlimited power, he was worshiped as a god, statues and temples were erected. Nero himself was engaged in tyranny: he organized theatrical performances, which forced citizens to attend, robbed and killed ordinary citizens with impunity at night, killed thousands of innocent people, perhaps even set fire to Rome, persecuted Christians. And Nero did all this with impunity, since the position of the emperor was practically sacred and untouchable.