My KKPsi nickname is Bubbles.
In Alpha Xi we don't give nicknames (in my chapter anyways). But there was one sister who called me D-Girl. I liked it, so I would try to use it every once in a while. If we could change our screennames on here (which I would love to do) that's what I would change it to.
Oh, and my husband calls me "Babe" - sometimes so often I think he's already forgotten my real name.
ETA: Oh yeah, my best friends from high school call me Donut. I don't know how they came up w/ that one.