WRT some posts here; while the Nirbhay is definitely nuclear-capable, it is not intended to be primarily nuke-tipped.
There are some other warheads which are singularly effective, viz. FAE warheads. Earlier this year, I had an opportunity to see a demo; which was awesome sans any mushrooms. Its already been inducted into some of the Missile Forces. Then there are new-age explosives such as CL20 which have passed the proto stage.
@
Tshering22; just for your info: up-ranging the Brahmos is a work in progress without any Russian involvement (for a number of reasons). In any case, do not lay too much store by the declared range.