IIT

IIT IIIT and NIT, are government colleges and have their own identity. Also, the students who get admission in these colleges do not to worry about the job (it does't depend only on college but also yourself that how much you have talent, skill). The environment is also good in colleges and one will grasp more knowledge here. In common, IIT, IIIT and NIT, are just the tag that one wants to get after class 12th. Also, the placements are very good in these colleges. In my opinion, one should definitely try for these colleges but at the same time, they must don't think that if they are unable to get this college then everything is over and nothing they can do. If they aren't able to pursue their UG programme in IIT, IIIT or NIT, then they should try for their PG programme in these colleges. It's all about students that how much they have guts, talent and skill to show whether they are a student of IIT or any other private colleges to the company.
Wish you best of luck. Please free to ask any other query.

Yes, you can appear for IIT-JEE examination after the completion Diploma of engineering or in the last year of Diploma. Through this examination you will be able to take admission in IIT in first year of engineering like a 12th pass students. You can choose any branch of engineering irrespective of your branch of engineering in Diploma. But it will be better for you if you choose the branch in IIT related to your branch in Diploma. There is no lateral entry seats in IIT. So, you can not take admission in IIT directly in the second year of engineering in any way. The only way to take admission in graduation course of engineering is to clear the IIT-JEE entrance examination. IIT-JEE examination is little bit tough examination and competition is very high. You must be well prepared before appearing in the examination. Beside this examination, you may appear in the Lateral Entry Entrance Test (LEET) to take admission in the second year of engineering in other engineering colleges. This is a state level examination. If you can clear this examination then through counselling, you will be able to choose a college from your state to take admission in the second year of engineering. It will save your one year.