“Cruz’s NBC eligibility is an individual case and controversy of a federal question that needs resolution in a federal court.”
Unfortunately, there is still an open question as to whether or not the Constitution allows the judiciary to overrule the decisions of the Electoral College and Congress with respect to the eligibility of the President-Elect and Vice President-Elect. A Constitutional Amendment could rectify the problem, but the establishment politicians have a chokehold on that process and remedy as well.
Another reason why this is a federal question needing resolution in a federal court.