I believe Nell is not the person that she was meant to be, but the person that society shaped and molded out of her. There are many situations to illustrate this but I will let the reader explore them. It took me a few months to come to this conclusion.
One of the most touching scenes I remember from this book is that of this woman interacting with her aging parents. Atwood captures the sadness and the tenderness that mingle in their interactions. She unleashes the longings of those moments in which you feel lonely because you are convinced that nobody would understand what you are going through. She does what a brilliant writer is expected to do: she puts into words what you are unable to say yourself when you are overwhelmed by emotions.
I also recommend her poetry book (Margaret Atwood's selected poetry 1976-1986) because it complements some of the tales that appear in "Moral Disorder"; it will help you to comprehend them better and to broaden your perspective on them.