Hello
ashisheeeeee , Mechanical Engineering from IIT Delhi is best because if you go for it then the tag of IIT is with you but NSUT cse is also good because it is in the top 7 best college list after IITs so its totally depend on interest because after CSE there are various career options but after Mechanical there are list options but from IIT Delhi there are various placements and all.

Hope it will be helpful for you :)