Hey Ankita! 

The Jee main cutoff for NiT's is based on jee main qualifying marks and all India ranks. 

The expected jee main 2019 cutoff for NiT's can be predicted from the previous years for NiT's is mentioned below.

Jee main 2018 cutoff - 

Common rank list - max marks : 350 min marks : 74

Obc - max marks : 73 min marks : 45

St - max marks : 73 min marks : 29

Sc - max marks : 73 min marks : 24

Wish you all the best!