مَلِكِ النَّاسِ
The Sovereign of humankind. (114:2)
إِلَٰهِ النَّاسِ
The God of humankind. (114:3)
Both malik and ilāh are genitive and explicate the earlier rabb. Grammarians can analyze these connected forms through apposition, explanatory apposition or adjectival description, depending on their treatment of the nouns.
The expressions do not denote distinct gods. They develop the invocation through three connected aspects—lordship, sovereignty and deity—before the danger is named.