Nord Twilight is slighty more useful than her sister Amber Twilight , since her ability is less indiscriminate. Sending 2 Illnesses onto an opponent's Chambermaid or Private Maid can be a very demoralizing and effective attack. Unfortunately, doing this requires that you discard all but one card from your hand, but considering that 2 Illnesses cost 8 Love , that's not as bad a deal as it sounds.
The other nice thing about Nord is that if you don't use her ability other players are likely to forget that you even have her Employed. If they let their guard down, you can double-illness them at just the right moment and do some damage.
Usually, the best reason to Employ Nord is to advance through the Private Maid stack and hire a better Private Maid later. Sadly, she is worth negative 4 VP, so you'll want to make sure to purchase an Illness to disable her by the end of the game if no other player beats you to it.