Can I still be served with a "Declaration of Nuisance" on my foreclosed home?

If the date of the ticket is after the date of the foreclosure sale, no, they can't do that.  Because at that time, you have no right to do anything about conditions on the property, other than remove yourself and your belongings.  So unless the nuisance being declared has to do directly with something belonging to you (a rusted-out car in the yard, for example), it's not your legal responsibility at that point.

However, if the foreclosure sale hadn't happened yet, the fact that the foreclosure has been started, or even gone to judgment, doesn't relieve you of legal responsibility for the property as long as you're in possession, or still the owner of record.