Could be, though Ted has shown a remarkable capability for self-delusion, so he could think he is. What I've said all along is that there are bonafide constitutional experts with legitimate arguments on both sides, and no precedents. Until SCOTUS makes a direct ruling, nobody really can say for certain what the law is. Cruz however has a much weaker case than Obama does, unless someone could prove Obama was born outside the USA.
SCOTUS has ruled on the nature of citizenship for those born abroad, although this is not the same as defining NBC, it does define a class of citizen that is not NBC.
Cruz knows the precedents. I think he is a sociopath, and has calculated (probably correctly) that no court is going to educate the public on the meaning of NBC, plus the weight of legal scholarship is that NBC is whatever Congress says it is. That's as valid as the weight of legal scholarship finding the RKBA to be a collective right.