Question: what is iz a nickname for?
Answer: Izzy is a common nickname for the given names Israel, Elizabeth, Isaac, Isambard, Isidore, Isidora, Isabel, Isobel, Isabelle, Isabella, Isaiah, Izzet, Isarn, Ismail, Isobel, Isra, Izebel, Izmara, Isobelle or Isam (عصام).