How old does a minor have to be to choose which parent he or she wants to live? Also does child support switch if the child goes to the other parent ?

The only “magic age” in Nevada custody law is 18, at which time (absent a guardianship for incompetency, etc.), no one has any right to determine where the then-emancipated person can live.  Until then, the wishes of a “child of suitable age and discretion” are one factor that a court must consider when determining a question of contested custody.  For an explanation, links to the relevant statutes, etc., see the materials posted here.  And yes, normally child support flows from the non-custodial to the custodial parent; there is an offset in joint custody cases.  A full explanation is at the same page of our website.