Dear candidate, please elaborate the course details, is it MCA. Elsewise, all colleges are good, IIIT is Grade A college with a very good placement record in comparison to other two. IIIT being the oldest among three, it is best known for Information Technology network education. NSUT and DTU are newly formed in years of 2018 and 2009. For comparing the colleges more specifically use Careers360 college compare tool. Link is given below:

https://www.careers360.com/compare-colleges

Good luck!