Yes, IIIT Delhi is better than some of the NITs, especially in terms of curriculum. Almost all NITs have outdated curricula while IIIT Delhi revises its curriculum frequently. Almost every engineering college has foundation courses like biology, chemistry, and physics in the first year which students have no choice but to study. These are a waste of time. IIIT Delhi introduces the CSE subjects right from the first year without wasting any time. Moreover, its curriculum is flexible so students get to choose what they want to study.
IIIT Delhi first-year students are taught Intro to Programming with Python, data structures and algorithms with Java, Shell Scripting, and Latex. Graph theory is introduced in the third semester followed by deep learning in the 4th sem. After this, an ECE student is free to choose any CSE stream and finally even sit for the CSE placements. No other engineering college offers such a flexible curriculum throughout India. IIIT Delhi also has an exceptionally good faculty base.
So, if you have an interest in IT, then IIIT Delhi is better than all NITs and many other good colleges in India.