NFPA Standard 70 is a national legislative of the USA and also can be used as good practice. IATF 16949 is a standard for the management system and that is a different perspective, requirements for electrical equipment are basic.
IATF 16949 is setting requirements for the system and NFPA Standard 70 is something you must comply with. NFPA Standard 70 has a short scope focused on electrical equipment.
Here are some articles that may help regarding IATF 16949: