I think it's a matter of style, I would find either acceptable, but I think capitalization in this context might be more common. Capitalization is used, I think, because "Chemistry" is a subject or course title, and not just chemistry in general. You might, perhaps informally, be studying chemistry in general, in which case, I would definitely not use a capital letter, but in the case of a "major" it is a formal course.
Capitalization is much discussed and debated, if you put the word into the Dictionary Look-Up box, you will find many threads on the subject in various contexts.
I agree it's a matter of style, particularly for degrees in subjects with simple subject names which are in common use. For degrees with complex titles, such as "Construction and Architectural Technology" (plucked at random from the internet), I would say it is more usual, and probably preferable, to use capitals, if only to emphasise that the actual name of the degree is being given.
Note: "awarded a degree in" is the UK equivalent of "majored in" (I hope!).