As I've said several times, there is no SCOTUS holding either way, but there is a strong, well-considered dictum, supported by much historical eveidence, that a child born on U.S. soil to two alien parents is a natural born citizen, and the Indiana court followed that-- which is what any court would do.
Nothing they did is supported by any SCOTUS decision.
Indiana simply took some editorial from 1 case and made it their decision, while not taking the "editorial" from multiple other cases which describe NBC = born in country to 2 citizen parents.
"THE VENUS, 12 U.S. (8 Cranch) 253, 289 (1814) (Marshall, C.J. concurring) (cites Vattels definition of Natural Born Citizen)
SHANKS V. DUPONT, 28 U.S. 242, 245 (1830) (same definition without citing Vattel)
MINOR V. HAPPERSETT, 88 U.S.162,167-168 ( 1875) (same definition without citing Vattel)
EX PARTE REYNOLDS, 1879, 5 Dill., 394, 402 (same definition and cites Vattel)
UNITED STATES V WARD, 42 F.320 (C.C.S.D. Cal. 1890) (same definition and cites Vattel.)"