Character Role Analysis
It seems that, more than anything else, Nora wants Torvald's love. After all, she's been wanting it for her entire marriage.
During the Helmers' final confrontation she says,
"I have waited so patiently for eight years […] Then this horrible misfortune came upon me; and then I felt quite certain that the wonderful thing was going to happen at last." (3.340)
The "wonderful thing" seems to be some proof of love from Torvald, something beyond pet names and little indulgences. Nora has a whole melodramatic scenario mapped out in her head. Torvald will find out her secret crime, then gallantly take all the blame onto himself. She, of course, would never let that happen, so she'll be forced to commit suicide in the black water of a frozen lake.
When this doesn't happen, and Torvald instead proves to be something of a coward who is actually only concerned with appearances, Nora's hope for the wonderful thing evaporates. She tells her husband, "For eight years I had been living here with a strange man […] I can't bear to think of it! I could tear myself into little bits!" (3.348).