Hi

When it comes  to subject which you must have in your 12th board examination then as per eligibility criteria to be eligible for admission in IIT, NIT etc for B.Tech/ B.E , you must have passed your class 12th board examination with following subjects:-

• Physics
• Mathematics
• Any one of -Chemistry, Biology, Biotechnology, Technical Vocational Subject. So, it's clear that chemistry is not mandatory

So it's ok if you have only physics and Mathematics and you don't have Chemistry in your 10+2, so you are still eligible provided you must have Biology, or Biotechnology, or Technical Vocational Subject in place of Chemistry.

For more information go through

https://engineering.careers360.com/articles/jee-main-eligibility-criteria

Thankyou