Engineering Entrance Exam

The last year closing ranks of NITs for few courses are given below in All India category for general candidates.
1. Civil Engineering : 40006 NIT Sikkim
2. CSE : 18900 NIT Mizoram
3. Mechanical : 39125 NIT Mizoram
4. MME : 45900 NIT Srinagar.

There is small difference between BITSAT and JEE Main syllabus. The JEE Main syllabus comprises the Physics, Chemistry and Mathematics while the BITSAT comprises the Physics, Chemistry, Mathematics, English language and logical reasoning. So preparation of JEE Main can be helpful for BITSAT also but

For computer Science department, minimum 99.50 percentile require.

If you are asking about International Institute of Information Technology (IIIT) Hyderabad, Than you have to fill the forms by using IIIT Hyderabad website only. Because IIIT Hyderabad is not the part of JEE Main counselling conducted by JOSSA. The admission portal of IIIT Hyderabad will be activate

You have not written about the home state you belong. However, your expected JEE Main AIR is below 31825. The last year closing rank in the asked branch was 26535 at NIT Nagaland. Hence your chances are moderate for CSE in NITs. However, you can get the following branches.
1. Civil Engineering at NI