This is an interesting question because most people definitely categorize Lady Macbeth as evil. I've even heard it defended that Lady Macbeth is more evil and more to blame for Duncan's death than Macbeth is to blame. This argument makes sense when you consider that Macbeth had decided not to kill Duncan, and Lady Macbeth verbally abused Macbeth enough for him to change his mind and go through with the assassination.
This question specifically wants to know "in what ways" is Lady Macbeth good. This doesn't mean that the question is asking you to prove that Lady Macbeth is a good and moral character. I really don't think that is possible. The question is simply asking you to find character traits of hers or things that she does that are good.
One thing that I think is good about Lady Macbeth is that she has ambition. So does Macbeth, and the play is making a statement about unrestrained ambition; however, the play isn't making a statement that having ambition is wrong. Lady Macbeth wants better things for her and her husband, and I think that is a good thing. It shows that she cares about the family unit that she exists in. She isn't only selfishly concerned about herself. She's willing to do the unthinkable to achieve her goals, but simply having high goals isn't evil.
I also think it is worth noting that she is a caring wife. She knows that Macbeth has ambitions of his own, and she knows that he doesn't have the courage to do whatever it takes.
Glamis thou art, and Cawdor, and shalt be
What thou art promised. Yet do I fear thy nature;
It is too full o' th' milk of human kindness
To catch the nearest way. Thou wouldst be great,
Art not without ambition, but without
The illness should attend it.
This shows deep insight on her part, and it shows that she is capable of some empathy on some level. I think it could be argued that this knowledge of her husband is what causes her to taunt, coax, and flatter Macbeth into killing Duncan.
Art thou afeard
To be the same in thine own act and valor
As thou art in desire? Wouldst thou have that
Which thou esteem'st the ornament of life,
And live a coward in thine own esteem,
Letting "I dare not" wait upon "I would,"
Like the poor cat i' th' adage?
Again, her efforts are directed at a terrible cause, but it does show that she is capable of being and becoming what her husband needs. That's part of being a healthy couple. Each person is strong in different ways, and those strengths work together to form a better marriage instead of working to tear it apart. She completes Macbeth, and he completes her. That's a good thing.
Finally, I think it has to be said that Lady Macbeth experiences guilt. That's actually great news. She does a terrible thing, but she feels guilty about it. That shows audiences that her moral compass is still active. It hasn't been completely destroyed or ignored. Knowing that there is still morality present in Lady Macbeth means that there is still goodness within her.