The percentage asking in nest is the total percentage i scored in phy, chem, bio , eng, and physical education
As per NEST eligibility criteria, At least 60% marks in aggregate in Class XII (or equivalent) examination from any recognized Board in India. For Scheduled Caste (SC), Scheduled Tribes (ST) candidates and for Persons with Disability (PD), the minimum requirement is 55%.
So the percentage includes your all subjects total.
Hope this helps. Good Luck.