Honestly, I would send the original Urdu nikkah nama anyway...just in case.
So you need these 3 things to send with your app:
1) Original Urdu nikkah nama
2) Translated English copy of your nikkah nama ATTESTED
3) Marriage certificate from NADRA
In the marriage certificate from NADRA, make sure that the marriage registration date is the day that your nikkah actually took place. That is the day you officially became married. Also go over the spelling of your names and all that stuff.
Thank you for your detailed answer, I appreciate, +1. Also if you do not mind, please could you clarify regarding the spouse educational documents. Really scared in sending original documents. Can send photocopies attested? Also same goes for NIC and birth certificate.
Also, remember to get a Family Registration Certificate (FRC) from NADRA for yourself and your spouse afterwards as well. These sort of official documents should help a lot.