If I get selected into NSIT and IIIT-H for computer science, which one should I choose? What are the pros and cons at each of them?

Here are the pros and cons of both NSUT and IIIT Hyderabad 

NSUT Pros:

1. NSUT has a very light academic workload so you can spend time exploring your passions
2. The crowd here is excellent and will teach you a lot during your time here.
3. NSUT is located in the capital city and enjoys a lot of benefits. Moreover, it’s located away from the hustle and bustle of the city in 
4. NSUT students get easy access to internships because Delhi has a lot of start-ups.
5. NSUT hostels are decent and the food served is much better than a lot of other colleges around. 

NSUT Cons:

1. NSUT has Computer Engineering instead of Computer Science & Engineering which comprised subjects related to hardware
2. The syllabus is outdated and no new developments in the field are covered. Moreover, core CS subjects are taught only after the 5th sem 
3. NSUT has a very pathetic research scenario and only a few professors are involved in good research work.
4. NSUT infrastructure and facilities are in a very bad state. There isn't a Wi-Fi facility on campus and no internet in hostels. 

IIIT Hyderabad Pros:

1. IIIT Hyderabad has the best CS curriculum in India. You will be mostly studying core CS courses.
2. IIIT Hyderabad has a rich coding culture and has produced a large number of coders. Some of them have even been featured at the top in online programming judges and competitions
3. IIIT Hyderabad has an active research culture and students are required to do research as a part of their course.
4. The placement scenario of IIIT Hyderabad is amazing and the best companies come for recruitment.

IIIT Hyderabad Cons:  Its curriculum is pretty challenging and very much CS-tailored making it difficult for students to explore their non-CS interests.

I will suggest you go for IIIT Hyderabad as it has better opportunities and an academic environment.