The Secrets of Isis (1975)

When an archaeology teacher unearthed an ancient Egyptian amulet, she learns that the item was a magic piece of great power. Researching the amulet's past, she decides to use that for its original purpose. Now whenever there is trouble, she dons the amulet and chants, "Oh Mighty Isis". With that, she transforms into the Egyptian goddess, Isis, and battles evil with the power of that deity.