Hello,
NITs are National Institute of Technology, these institutes are among the top ranked engineering colleges in India. Currently there are 31 total NITs in India spread across the states of India.
First NIT was stgarted in 1886 and many more came up in 1960s and 2010.
IIITs i. e. Indian Institutes of Information Technology (IIITs) are a group of autonomous institutions offering technical education focused on the Information Technology and Communication Studies. They are comparatively younger and are less popular than NITs and IITs.
NITs hold greater brand value and future career prospects as of now, but, IIITs like IIIT Hyderabad and Allahabad are standing at par with top NITs.
Follow this link for more
https://www.google.com/amp/s/engineering.careers360.com/articles/list-of-indian-institutes-of-information-technology-iiits/amp
Good luck

IIITs are best. But it also depends in which IIT or NIT you are talking about . 

The basic difference is IITs are INDIAN INSTITUTE OF TECHNOLOGY & NITs are NATIONAL INSTITUTE OF TECHNOLOGY. ... admission in IITs based on JEE ADVANCED score while getting admission in NITs is based on JEE MAIN. IITs are superior than NITs in every aspect (except some new IITs). IITs are more good in terms of placement and academics. You can do more better in IIT.