I agree with the above user in that I've never heard of Tasha used as a nickname for Natalia. But Natasha is not the only possible nickname. I'm Russian, and my friend, whose full name is Natalia, goes by Nata, another nickname for Natalia.
Tasha is the name of a character in the children's show Backyardagains.
― Anonymous User 7/12/2008
Natasha is my name, and I like to be called this nickname because it means people don't call me Natalie or Nicola. I've even had to put up with names like Rebecca and Samantha, just because they all have 3 syllables.
― Anonymous User 11/15/2008
Lt. Tasha Yar (sometimes called 'Natasha' though I believe it has been established that 'Tasha' is in fact her given name) is Chief of Security aboard the USS Enterprise 1701-D during the first seasons of the television show Star Trek: The Next Generation.
My Name is Natasha but it is shortened to Tasha. I prefer the name Ash but no one I know calls me that. I don't really like my name but I like the fact it means Christmas or birthday in Russian (Apparently!).
My best friend's name is Tasha. She's amazing. I love this name. You have to be careful though with middle names because it can be tricky to pair with.