The constitution does not define NBC, just that the President needs to be one. The laws that do define this are 1790, 1795 and 1934. The definition of NBC has changed.
As I understand it as an originalist interpretation, one must be ‘ of the soil’ or ‘of lineage that shows loyalty to the sovereign ( the King of UK prior to The President)’
Then we get into whether both/either the father and/or mother needed to have been citizen when giving birth overseas.
The 1934 statue gives out several cases, for example.
The constitution defines citizen though. Cruz is a citizen only becuae a statute exists to cover his cirumstance of birth. As a matter of law, that makes him naturalized.