Hello aspirant, the JEE mains exam conducted for admission of student for B.E/ B.Tech courses in NITs, IIITs and other GFTIs. Through JEE mains you can get admission in NITs for various branches like CSE or ECE or MECHANICAL etc for a  4 year B.Tech degree.

NIMCET is an exam conducted for admissions to MCA programmes. The exam is conducted for admission in Master of Computer Application in participating NITs.

Without giving JEE mains it is not possible to get into NITs if pursuing a 4 year B. Tech course.

For detailed information about NIMCET visit - NIMCET Exam 2021 - Registration (Started), Syllabus, Admit Card, Result, Cutoff (careers360.com)

For information regarding JEE mains exam visit - JEE Main 2021 - Latest News, Exam Dates, Registration, Admit Card, Result, Syllabus, Pattern (careers360.com)

Best of luck!!