It will be quite difficult for you to get chance in NITs with 42105 SC rank. You may opt for private engineering colleges or drop a year to prepare for JEE Main 2021.

Following are some best private engineering colleges.

1. BITS Pilani
2. VIT Vellore
3. SRM University
4. KIIT
5. Thapar University
6. Manipal Institute of Technology
7. Lovely Professional University
8. Chandigarh University
9. RV College of Engineering
10. BITS Mesra
11. DA - IICT
12. KJ Somaiya College of Engineering

However you have a chance to get a list of prescribed colleges against your rank. You just need to use JEE MAIN COLLEGE PREDICTOR. Click the link below, put necessary information and get result instantly.

https://engineering.careers360.com/jee-main-college-predictor?icn=QnA&ici=qna_answer

All the best.