Yes, you can get admission to NITs based on your JEE Main exam score. Here's how:

1. Eligibility Criteria:
To be eligible for admission to NITs, you need to fulfill certain criteria:
- You must have passed your 10+2 or equivalent examination with Physics, Chemistry, and Mathematics as compulsory subjects.
- You should have scored a minimum of 75% aggregate marks (65% for SC/ST/PwD candidates) or be in the top 20 percentile of your respective board.
- You must have appeared for the JEE Main examination.

2. Qualifying JEE Main:
- JEE Main is a national level engineering entrance exam conducted by the National Testing Agency (NTA) for admission to various engineering colleges, including NITs.
- It consists of two papers: Paper 1 for B.E./B.Tech. courses and Paper 2 for B.Arch/B.Planning courses.
- You need to appear for Paper 1 to be eligible for admission to NITs.

3. JEE Main Score Calculation:
- The JEE Main score is calculated based on the normalization process, which takes into account factors like the difficulty level of the exam, the number of candidates appearing, and the average performance of candidates in each session.
- The final score is calculated using the percentile score, which indicates the percentage of candidates who have scored equal to or below your score.

4. JEE Main Rank:
- Based on your JEE Main score, a rank is assigned to you, which determines your position among all the candidates who appeared for the exam.
- This rank is used for admission to NITs and other engineering colleges across India.
- The Joint Seat Allocation Authority (JoSAA) conducts the counseling and seat allocation process for NITs based on the JEE Main rank.

5. JoSAA Counseling:
- JoSAA conducts a centralized counseling process for admission to NITs, IIITs, and other participating institutes.
- Candidates need to register themselves, fill in their choices of courses and institutes, and participate in the counseling process.
- Seats are allocated based on merit, preferences, and availability.

6. Seat Allotment:
- Once the counseling process is complete, seat allotment results are declared.
- If you are allotted a seat in an NIT, you need to confirm your acceptance by paying the required fees and completing the admission formalities.

In conclusion, admission to NITs is based on your JEE Main exam score, which determines your rank. The counseling process conducted by JoSAA plays a crucial role in seat allocation. Make sure you meet the eligibility criteria and perform well in the JEE Main exam to increase your chances of getting admission to NITs.