If I dont have Nalia in my group, will she get kidnapped. Since she is the most worthless NPC in the game I dont want to be dragging her around unless it has a purpose.

Spoiler. That's okay. Wait a while after finishing her quest, then put her in your party and head to Athkatla. You'll be approached by some suck telling you to go to a funeral. Go ahead, talk to everyone, then wait 24 hours and Nalia will be kidnapped. In other words, you don't have to have Nalia in your party for two weeks before the quest comes up, but two weeks needs to have passed, and you have to have her in your party to start the quest.