Act 1

Nora doesn't tell lies, as much as she indulges in keeping secrets. She hides the fact that she has had to borrow money and pay it back, she hides her interactions with Krogstad and Dr. Rank. She also urges her children to "keep things secret." It isn't about lying, it's about hiding.

Absolutely, she should not be regarded as a liar but she possesses a very peculiar nature a bit like Hedda Gabler (Henrik's character in another play). In fact she is an egocentric and keeps a different nature. She is spendthrift for herself but miserly for others as she doesn't facilitate Mrs. Linde in her house in act 1. She is a bit calculating woman who only thinks of herself.