You can check out the cutoff of the NITs from the link given below

https://engineering.careers360.com/articles/jee-main-cutoff-for-top-nits

Here you will be able to see the cutoff of various colleges in accordance with 2018. 

Further you can apply for the various government college that offers admission on the basis of the JEE main marks.

If you're having any government college or national institute of technology in your own state then it will be very helpful to you getting admitted to that college.

Good luck!