Which is better degree-MTech in applied chemistry or BTech in chemical engineering?

It's not that one is better than the other; it's just that they are different. The question should be, "which one is best for me?" In order to determine that, you must first acquire a vision; a specific and clearly articulated picture of the future you intend to create for yourself. This vision should be based on a passion for what you want to do and the benefit it will bring to others as well as yourself. Once you acquire that vision, your path will become clear.