There is nothing wrong with using the name Yazan, because there is no reason not to do so in sharee’ah. Yazan is the name of a valley in Yemen. It says in al-Qamoos al-Muheet: Yazan is a valley, the original name of which was Yaz’an; it is also the name of a tribe from Himyar. Dhu Yazan was a king of Himyar because he protected that valley. End quote.
So it is the name of a valley and the name of a tribe from Himyar.
But it would be better than that to call the child ‘Abd-Allaah or ‘Abd al-Rahmaan or Ahmad or Muhammad, or the name of one of the Sahaabah, or a name that carries a good meaning. This is better than calling him by the name of a valley.
For more information, see the answer to question number 7180.
And Allaah knows best.