Dear aspirant hope you are doing well. It's difficult to predict because cut keep changing every year depends on various factors.

1. No of seat available.

2. Difficulty level of exam.

3. No of student appear in exam...

It's difficult to get seat in top Nit colleges to get admission because to get seat in M. Tech with sc category, candidate must score 450+ score for civil engineering. You can check out the cut off of top NIT colleges. Link is given below.

https://engineering.careers360.com/articles/gate-cutoff-for-nits

you can check your chance to get seat in M. Tech colleges according to your score by using Gate college predictor tool.

https://engineering.careers360.com/articles/gate-college-predictor/amp

Hope it's helpful..

Thank you