The children are precious to Nora. They are also her figurative counter-part, representing a mode of being that Nora continues to inhabit as an adult. From the play's opening, we see Nora surreptitiously sneaking cookies like a child.
Her day is filled with constant acts of subterfuge—some minor, like sneaking macaroons, and some of the utmost importance, like paying back a loan that saved her husband’s life.
Symbolically, it is important to note that Nora is most "herself" when she is with her children. By the end of the play, we see that this is true because, like the children, Nora is an unformed person without a true identity of her own. The playful and gratifying time she spends with her children can be viewed as an indication of Nora's state of development.
Another element of meaning associated with the children comes from Nora's personal history. Nora was raised without a mother figure. She was raised by the same nurse that lives with her during the action of the play, Anne-Marie. This fact impacts Nora in at least two ways.
She is able to leave her children in the end because she will be leaving them with the person who raised her, a competent surrogate mother. This is akin to a realization that children do not need both parents, at least not in an absolute way.
Though Nora wanted to give her children a loving mother in their lives, something she never had, she ultimately is driven to repeat history and to leave her children without a mother.
Part of what leads to Nora's decision to leave her children without a mother is the idea that she might corrupt them and ruin their lives. When the idea is planted that Nora's crime of forgery may ruin her children, she begins to fear the worst.
Torvald voices this opinion when he mentions that people like Krogstad end up with moral deficiencies because a mother has failed in her responsibilities.
In deciding to leave them, we can see this fear as well as her confidence in the abilities of her nurse to raise the children. The children can be seen as Nora's legacy here, and she must decide how to shape that legacy: risk corrupting them by staying in her marriage and remain a child herself or leave them motherless and go off to develop an identity of her own.