Dear aspirant

The choice entirely depends up to you . If your passion lies in software engineering or computer programming the you should opt for IIT nagpur and if your passion lies on core industry or chemical engineering then you should opt for VNIT nagpur . But if you ask institute wise which is better than VNIT nagpur is obviously the better choice than IIIT nagpur as it has better placement scenario

You can check VNIT cut offs in our link

https://engineering.careers360.com/articles/jee-main-cutoff-for-vnit-nagpur

and you can check any detail about IIIT Nagpur here

https://www.careers360.com/university/indian-institute-of-information-technology-nagpur

Best wishes.