Cruz IS a Natural Born Citizen.
The only way you get to be a citizen of the USA is to either be Natural Born or go through the Naturalization process.
Cruz DID NOT NEED to go through the naturalization process because he received his citizenship through natural birth from his Mother.
The law granting citizenship to Cruz did require a process, that he return to the United States by a date certain and remain there for a period. This requirement was later repealed. A “process” is not a requisite condition of naturalization, dependency upon Acts of Congress is.
When a family immigrates to the United States, the adult mother and father go through a "naturalization process." The children do not go through a "naturalization process." They do not have to take any tests, they do not have to swear any oaths, they do not have to stand in front of a judge.
Their "naturalization process" consists of precisely nothing.
So too do babies naturalized at birth by a law passed by congress. They don't go through a "process" but they are still naturalized by Congress' power of naturalization.