if you wish to persue integrated msc,doing it through NEST is the best option.NISER.If you have CGPA greater than 7.5 in physics, chemistry and biology you can directly seat in the BARC for the interview.NEST is used for admission in NISER and UM-DAE CEBS mumbai, they train you expose you to research in basic sciences.They provide you the best faculty and facilities to direct your mind towards basic research.After finishing your msc you can opt for phd in reputed institutes like HBSC TIFR BARC IISER etc. and have the high chances of getting selected if you are passing out from these instututes.Also you can apply for phd abroad.If you dont want to go for phd degree you have other options too such as Scientific officer,MBA ,Lecturership,MTEC etc

Dont forget that the scope is what you create !

all the best