Natasha is a slur used to describe Russians in a derogatory way. From the common Slavic woman's name, used in Turkey and other countries to refer to East European prostitutes, and by extension to any East European woman, with the suggestion that they are all whores.
The word Natasha is a racial slur that has been used historically to degrade and dehumanize russians. The word is still used by some people for this purpose, and it is seen as offensive and hurtful to russians. If you are unsure about whether or not it is appropriate to use the word Natasha, it is best to err on the side of caution and avoid using it in any situation.