You see Hans knows very well that he had a huge groups of fans and supporters and that those supporters were not very smart and supported him even after the evidence against him got more and more obvious and incontrovertible. I remember that even after he led the police to her body there were huge discussions on slashdot and some people were still talking about how he was still somehow unfairly treated by the justice system and Nina somehow brought this about on herself.
Psychopaths are very adept at using people, and I bet Hans just feels that there still are some people he can use out there. The problem is that after he showed her body to the police even his most ardent fans would have to admit that he killed her.
So he comes up with this story that he wants to clone her to give her the happy childhood that she missed. (Notice that he did not say that he wanted to give her her adulthood which she missed because he killed her).
Obviously a smart and practical person like him knows that this will not work. Even if cloning were possible, you would create a different person. It would be a different person with the same DNA but a different person nevertheless.
So yes, he is just a psychopath that wants to get another bunch of money from the fools that used to believe him.