After only 3 years of independence, which state returned to Nigeria's control after losing almost one million civilians, mostly to starvation?

Answer: Biafra

Explanation:

After two-and-a-half years of war, during which almost two million Biafran civilians died from starvation caused by the total blockade of the region by the Nigerian government, Biafran forces under Nigeria's motto of "No-victor, No-vanquished" surrendered to the Nigerian Federal Military Government (FMG)