Branch change in NIT There are several rules that some specific percentage of top students are only allowed to change branch but is in your case you will be in Computer Science and Engineering so no one is going to change branch to other branches there for you will be the highest scorer to change the branch and generally no one go for chemical engineering from other branches also there for if you even Golu CPI so then you will be able to change the branch to chemical engineering.but first of all if you are able to get Computer Science and Engineering and you are interested in chemical engineering then you can take chemical engineering very easily because there is less competition in chemical engineering unit lowering rank you will get chemical engineering