Sure.
Use a data management campaign like so. This can be a batch or a trigger:
Smart List: Country (or State) IS EMPTY
Flow:
Change Data Value: If Country IS EMPTY, then Country IS {{lead.inferred country}}
you can do that for states and provinces as well.
It's worth reviewing the existing data to make sure the Inferred Country conforms to your Country Picklist (if you're using one). If you are using a Country Picklist, then you'll need a really long set of Choices to assign Country properly.