Hello

It would be difficult to tell you exactly about the marks required for admission as the cutoff varies ever year depending on many factors. Some of the determining factors are

Number of seats available
Number of candidates appeared in the exam
Previous years’ cutoff trends
Difficulty level of the exam

Cutoff also varies engineering stream wise. You can check the previous year NIT Trichy cutoff using the link below for reference and to have an idea about the ranl required-

https://engineering.careers360.com/articles/jee-main-cutoff-for-nit-trichy

Good Luck!