Regardless of whether a state is a “swing” state or not, there are people who move to each state. For example, college students from non-NJ places who choose to attend colleges in NJ may move there and live there at least 3/4 of the time they are in college.
Yes, college students and others who reside in various places through the year may have a choice of where to register and vote, and whether each location is a “swing” location may affect their decision.