Why Nubia?
As we now know that Africa was the home of the First Mother, the Mother of the human race, we can only assume that the African/Nubian Mother Goddess culture was particularly potent as it was in Africa that the Mother Goddess culture first came into being and subsequently spread throughout the preliterate world.
In Jungian terms, such shamans were powerfully psychic humans capable of things we know today as remote viewing, astral voyages, telepathy, prophecy, healing and the like. These powerful shamans didn't impress with words, but psychic deeds. Word spread fast if the deeds were powerful, and because of this, they quickly developed followers.
As to where she lived in Nubia, I tend to favor Upper Nubia between the the second and third cataract, which was a fertile plain that had a long, continuous history of cultural development. Archeological studies have shown that Nubian hunter/ gatherer tribes were living in this area even during the "wild Nile" of 10,000-7000 B.C. as evidenced by this very good site on prehistoric Egypt. This area also eventually gave birth to what is known as the pre-Kerma herding culture around 5000 B.C.. It is a distance of about 750 miles from Giza.