One of my friends is a B.Tech graduate and has experience from both IIT and NIT. After passing JEE Main on his first try, he was not prepared to take the JEE Advanced. It was so because he doesn't want to be a dropper and he chose NIT Bhopal. 

There is no distinction between the standard of teaching at NIT and IIT, but there are still exceptions. Although they have Ph.D. faculty, you will be taught by M.Tech faculty. Mass bunks happen all time. All of this fuelled my friend’s urge to join IIT.

• From January, he began to study again and passed the JEE Main exam, as well as qualify for the JEE Advanced exam.
• He had the option of choosing from all of the latest IITs in CSE, but he chose IIT Patna Mechanical Engineering because it was closer to his hometown. 
• He also realized that coding was not his future.

Now, on the first day of orientation, IIT will greet you in such a way that you will make a strong impression. You can find seniors to be incredibly helpful. Faculty are really nice, and they will often inquire about ragging in your first year because it is absolutely forbidden, and just for the record, the IIT Patna campus is a ragging-free campus. He adored the school, campus, teachers, and services. Since coming to IIT from NIT, he has learned a lot.

Always choose any IIT you want over NIT. However, the choice is solely based on every individual’s professional experience and judgment. You may disagree with it, so always consider researching more.