You can email the admissions department with a request to change your major from nanoscience to engineering as if you want engineering you have to do it now (and be accepted).
https://vt.edu/admissions/undergraduate/apply/policies.html#appchange
As you were deferred in Early Decision for nanoscience I would think with Engineering being a much harder department to get in to that may be self defeating.
I believe though if you list it as Engineering with second choice nanoscience you are able to get in nanoscience if rejected from Engineering. I’m not sure if that is a disadvantage with them knowing its your second choice.