Thanks for A2A

With regards to the curriculum,  I can assure you with the top 10 NIT's would be following the eniterly same (or almost similar) curriculum and their course is also inlined with the curriculum followed by the IIT's

With regards to IIIT's, since they are being bit new so they definitely follow slightly modern/revised syllabus and I've heard have more focus/exposure to the current interest in CSE feilds like Machine Learning or Android Development etc.

I would advise you to get in touch with your elder relative who hold's first hand experience studying at IIIT,he can tell you the better insights about it!