Well, everyone calls me Nat because it's short for Natalie.
I have another nickname though, natz0r. It came about when it was cool to add 'z0r' at the end of your nickname but it sort of had to flow. I think I was taking the piss out of people who did that and it just stuck, well my best friends still call me it and I even use it for twitter and facebook.
My other nickname is natski, this came about by my friend Lisa, adding the first part of my name and the last part of my last name, thus creating natski. This stuck and many people still call me it. To add a pinch of coolness, my other friend Tamar added yoghurt after natski, as in the yoghurt brand, Ski.