Cut off marks in NITs vary according to the category and state quota.

You have to score more then 130 marks in JEE Main to get ECE branch in NITs in general category other state quota.

To get ECE branch in top NITs you should score more then 200 marks in JEE Main.

Good Luck!!

You can see rank requirements in jee main using below link.Its pretty tough to say about jee maina marks requirement because previously board marks too were counted in rank list generation except last year.so,there can not be analysis of marks trends for a period of some years.however,before jee mains system,only marks were used in aieee rank,but the scenario has completely changed in so many years,in terms of competition,question paper toughness,no of NITs etc

https://www.google.co.in/amp/s/engineering.careers360.com/articles/nits-cutoff-for-btech-electronics-communication-engineering%3famp

Just have an idea of marks vs rank through this link:-

https://www.google.co.in/amp/s/engineering.careers360.com/articles/jee-main-result-marks-vs-rank%3famp