Hello!
To qualify for NIT, you need to clear the cutoff in JEE-Mains. If you qualify in JEE-Mains, the aggregate marks is considered for qualifying for JEE-Advanced. So, 75% aggregate is required (the marks in english + marks in 4 subjects).
Hope it helps.
Regular exam updates, QnA, Predictors, College Applications & E-books now on your Mobile