Choosing subject wise ece at any cost but comparing the two institutions you have mentioned is very difficult nit trichy has a nirf ranking of top 10 but mnnit has nirf ranking of 42 but don't go on nirf ranking as they do not tell the true picture mnnit has the best average package among all nits in india also packages here are breaching half a crore mark and in mnnit ece the placement percentage this year is about 94% and ice placement percentage at nit trichy is about 97%(2019-20) so you can see that the competition is neck and neck so it ultimately boils down to you which you want to take but looking at the stream and other prospects mnnit is a good choice otherwise choose wisely.