Legal Question in Real Estate Law in

(1) Is the Nomination from to be signed by both the holders ?

Yes, it must be signed by both the holders.

(2) What happens if the First Holder dies ? what is a title of the second holders

You may put the terms in the nomination as per your question. Second holder is equally owner and will continue to be so, in case of death of first holder.

( 3) Is it require to nominate second holders in Nomination Form by the First holders ?

In case of joint ownership one can nominate only his share. Second holder will have to nominate on his/her behalf.

nomination is different from ownership. once ownership is in the joint name, in case one of them is no more, the other automatically becomes the owner for entire flat. nomination does not mean joint ownership.