See all the fields you have mentioned here are equally good in their respect and each of them are gonna be equally important in future.

Whether it is petroleum or nuclear specifically or any other engineering each one of them has good scope as manufacturing sector will be getting advanced in technology but won't shut down any time in future. There will be always demand for new technology from engineers.

Currently in engineering it is computer science engineering which is capturing market and growing at a very fast rate. Not only this it is also getting merged with other engineering fields in order to come up with new technology in every field.

Coming to management side any company whether it is manufacturing or service sector it requires a team to manage it properly, market it's product and sell it, manage the operations and financial conditions of the organization. So there is endless scope in corporate sector which has grown to a large extent on last few years along with digital technology.

And where you are gonna stand among all other engineers or managers depends on the hard way you study and from the good college you will be pursuing your engineering or MBA degree.

P.S. - You can also do b-tech first as your graduation and then pursue MBA. Around 80% of the students doing MBA are engineers.