I don't think angels are the results of Nephilim. We aren't told who exactly the "sons of God" were in Genesis 6. I tend more toward believers (children of God) not angels. Angels were never called sons of God.
Heb 1:4 So he became as much superior to the angels as the name he has inherited is superior to theirs.
Heb 1:5 For to which of the angels did God ever say, You are my Son; today I have become your Father? Or again, I will be his Father, and he will be my Son?
Heb 1:6 And again, when God brings his firstborn into the world, he says, Let all God's angels worship him.