Hey Krishna ,If we consider past two years cutoff you are not eligible to got NISER .

In 2017 :-

1st round - 624

2nd round - 671

In 2018 :-

1st round - 552

2nd round - 654

From this you got a idea about cutoffs.

For 1st round it's about 500 and for 2nd round it's about 600.

Hope it helps.

All the best!!