In A Dolls House, can it be argued that the ending represents Nora's self-realisation or a moral crime?
I would argue that it is possible to consider that both of these options are true. If we analyse Nora's words in the final scene of this play where she has her confrontation with her husband, Torvald, it is clear that Nora through the course of the play has reached self-realisation. Consider her very frank assessment of her role in the marriage and her understanding of the impact of both Torvald and her father in her life:
I have been performing tricks for you, Torvald. That’s how I’ve survived. You wanted it like that. You and Papa have done me a great wrong. It’s because of you I’ve made nothing of my life.
Nora's summary of her marriage as nothing more than "performing tricks" for Torvald aptly captures the sense in which her marriage has been one where she has been patronised and subservient, treated like nothing more than a child. We definitely therefore see Nora growing up at the end of this play.
However, as the second option makes clear, this is at a terrible cost. Nora does manage to achieve self-realisation and strikes out independently to live the kind of life that she was unable to live before, but only at the expense of robbing her children of their mother. One could argue in this sense that her action in abandoning her life is actually very selfish, as she only thinks of herself in leaving and does not think of the impact of this act on her children. Therefore it is equally possible to argue that this represents a moral crime.