Which, among IIIT D, IIIT H, DTU and NSIT, is better for CS?

Don’t even think about this much and right away it is for IIIT Hyderabad, it will never disappoint you in CS. In fact, If CS is your only preference then the only options better than IIIT Hyderabad are the 5 old IITs. 

Here is why I recommend you to go for IIIT Hyderabad 

• IIIT Hyderabad has better research culture and facilities in comparison to the other choices. have. The faculty pool at IIIT Hyderabad is much more qualified than these institutes too. 
• Students planning to pursue MS will get better exposure and opportunities at IIIT Hyderabad than any of the other aforementioned institutes.
• The CS placements of IIIT Hyderabad are at par with the CS placements of the old IITs. IIIT Hyderabad students get placed in IT giants like Facebook, Google, Uber, Tower Research, and Microsoft
• IIIT Hyderabad students actively participate in coding and programming contests like Google Summer of Code. 

So, IIIT Hyderabad is the best option for you unless you are not interested in coding.