Dear Aspirant,

With this JEE Mains rank , your chances to get into top NIT's are very low. But you can opt for CSAB spot counselling. There you have some chances to get branches like Civil, Chemical in some new NIT's. And let me clear you , you can get admssion to IIT's only on the basis of your JEE Advance score. JEE Mains score is only for admisson to NIT's, IIIT's,  GFTI's and govt. colleges.

To know more about CSAB counselling, you can refer to the link given below.

https://www.google.com/amp/s/engineering.careers360.com/articles/csab/amp

Hope this helps.