Nice slacks, a nice blouse, and a nice jacket sounds good. Make sure you are wearing appropriate shoes. (Simple flats would be fine if you have them. This is not the time for platforms or stilettos.
) It probably goes without saying that you should be well-groomed (clean hair, discreet makeup and jewelry, etc.) and on time. The thing about an interview at the HQ of a large company is that it is an occasion to show that you know the "right" thing to do, even if you never dress that way again during your entire college career. It doesn't mean you have to be devoid of personality, but it shows maturity. Good luck!