Hi janabhi!

I think for u getting seat in cse or ese in any nit is impossible. Because may be your rank in jee mains exam is1.500k plus so, for u it is impossible. But once try in spot round because you are not getting seat in first seven rounds so apply for spot round may be u have chances to get seat but not in desired branches mainly in cse and ece branches.

With your percentile score it may be a little difficult to get into NITs like Warangal or Agartala, Jamshedpur or any other in the gamut but for CS/IT you can definitely look out for NIT Durgapur as they may accept your percentile for CS branch. And if that also doesn't work then check out for BITS Pilani as it's also considered with same importance. 

All the best