Hi aspirant,

If you are from science background and have one of the following educational backgrounds. you can surely be eligible to appear for JEE main and take admission into NIT, IIT's.

• The final examination of the 10+2 system, conducted by any recognized Central/State Board, such as Central Board of Secondary Education, New Delhi; Council for the Indian School Certificate Examinations, New Delhi; etc.
  Intermediate or two-year Pre-University examination conducted by a recognized Board/ University.
  Final examination of the two-year course of the Joint Services Wing of the National Defense Academy
  Senior Secondary School Examination conducted by the National Institute of Open Schooling with a minimum of five subjects.
  Any Public School/ Board/ University examination in India or any foreign country recognized as equivalent to the 10+2 system by the Association of Indian Universities (AIU).
  Higher Secondary Certificate Vocational Examination.
  A Diploma recognized by AICTE or a State board of technical education of at least 3 years duration.
  General Certificate Education (GCE) examination (London/Cambridge/Sri Lanka) at the Advanced (A) level.
  High School Certificate Examination of the Cambridge University or International Baccalaureate Diploma of the International Baccalaureate Office, Geneva.

Note-- You are only eligible for jee main for consecutive 3 years and jee advance for consecutive 2 years from the year you appear for intermediate or relevant exam.

Hope it helps!!