It depends on the course you're interested in and if you're in the home state category or not. If you are from your native state, you should have a minimum of 130 points; if not, add 20 to 30 points more.
Recent cut-off stats of NIT Trichy for popular courses is given below.
Branch | General rank | OBC rank |
ECE | 847- 3022 | 425 - 1011 |
Chemical engineering | 3225-12056 | 1972 – 4207 |
Computer science engineering | 163 - 781 | 108 - 242 |
Mechanical engineering | 2468 - 6,591 | 1194 - 2,139 |
Electrical & Electronics Engineering | 954 - 5,381 | 932- 1,717 |
Metallurgical and Materials Engineering | 12765 - 20,809 | 4407 - 6,908 |
Anywhere between 200 and 300 will get you a good nit with the branch you're after. So 200 should suffice.