Dear student,

First of all congratulations, if you could get computer science engineering and electronics communication engineering in NIT Mizoram, NIT Meghalaya, NIT Manipur, IIIT Surat and IIIT Vadodara.

Now if you are confused that among these Institutes which to take then according to me, you must go with IIIT Surat.
Because these nits are low and you will not get very much good study exposure.

But as coming to the iiits then between iiit varodaraand IIIT Surat , IIIT Surat is best between these two.
So if you can get any of the computer science engineering or electronics and communication engineering branch in IIIT Surat then definitely you must go for it and it will be the best option.
The placement record for IIIT Surat is also very good among these colleges that you have mentioned in your question.

Also if you have given jee mains this year then check out our JEE mains college predictor tool to get an appropriate and of the colleges that you can get on the basis of your JEE mains rank :-

https://engineering.careers360.com/jee-main-college-predictor?icn=QnA&ici=qna_answer