Of course, this play has so much to do with reality and façade, and this is something that the key characters represent brilliantly. One cannot but help be struck by the relationship of Nora and Helmer and its artificiality from the very first lines of the play:
Helmer (from his room). Is that my skylark twittering out there?
Nora (opening some of the parcels). It is!
Helmer. Is that my squirrel rustling?
Helmer. When did my squirrel come home?
Note the childish names that Helmer comes up for his wife, and the way that Nora plays the role that he gives her by accepting those names.
However, the play is the story of Nora's gradual realisation and acceptance of what her life and her marriage is really like, and how she is utterly trapped and imposed upon in her position. Note this key speech from Nora in Act III:
You've always been very kind to me. But our home has never been anything but a playroom. I've been your doll-wife, just as I used to be Papa's doll-child. And the children have been my dolls. I used to think it was fun when you came in and played with me, just as they think it's fun when I go in and play games with them. That's all our marriage has been, Torvald.
Here we see a Nora who now is speaking directly, after playing the role of her husband's doll so well throughout the play. She has come to see her life and her marriage for what it is, and key to this is she has seen that her relationship with Torvald is just a continuation of her relationship with her father--she has never been allowed to develop into an independent, mature female, as her relationships with men have always kept her as a "doll" or a little girl.
Thus it is Nora who, out of all the characters, changes most from the beginning to the end of the play in her dialogue, as she becomes more and more direct and truthful about her life and her relationships.