Does nikaah terminate with talaaq or iddat?

If this is the first or second talaaq, then your husband can revoke the talaaq as long as your iddat remains. If he revokes the talaaq, your iddat will end and you will remain in his nikaah. However, if he does not revoke the talaaq and your iddat terminates, you will come out of his nikaah and thereafter he will not be able to revoke the talaaq. Nevertheless, if you both mutually wish to reunite after the iddat terminates, then a new nikaah will have to performed with a new mahr.

And Allah Ta'ala (الله تعالى) knows best.