Are Anunnaki the “fallen” angels of the Bible who “fell” to Earth and copulated with the daughters of men, who had giant children, “the Nephilim”?

They are not angels so that is a misnomer. They did come to Earth and they did interbreed and the Nephilim refers to the progeny of these “gods from the sky” who were the Anunnaki, not truly deities but were certainly awesome figures from their appearance and their technological capabilities.