"chief authorities" is correct and usable in written English.
You can use it when you are talking about people with the highest authority in a certain domain. For example: "The chief authorities of the city convened to discuss the new policy."
The chief authority in the Old Catholic churches is the conference of bishops.
"Lay down and be still!" said Yamilette Diego, a chief authority figure in his life.
Throughout the antique revival of the Renaissance, the classical phase of the Baroque, and in the Neoclassical period, his work was the chief authority on ancient classical architecture.
Application to hold the Games is made by the chief authority of the city, with the support of the national government.
The colonel acknowledged that he and John D. Altenburg, the chief authority for the military commissions, had known each other's families for years and had attended family functions together.
Caesar is the chief authority, but he may have received some of his facts from the Stoic philosopher Poseidonius, whose account is often confirmed by early medieval Irish sagas.
Bian Qiao was looked upon by many as the most knowledgeable user of pulse lore, although physician Wang Shuhe, who lived some 750 years later, is generally accepted as the chief authority on this peculiarly Chinese medical subject.
The chief authority in Berry eventually passed to the viscounts of Bourges, who, while recognizing the royal suzerainty, preserved a certain independence until 1101, when the fief was sold to the crown.
Bian Qiao was looked upon by many as the most knowledgeable user of pulse lore, although Wang Shuhe, who lived 750 years later, is generally accepted as the chief authority on this peculiarly Chinese medical subject.
