Do angels have a sin nature?
No. Angels, unlike flesh and blood men and women, know Almighty God in allHis fullness, that is, His Power and Glory.They were created perfect with perfect knowledge. They were also createdwith personal volition or "free will". They can make choices.One third of the angelic forces chose to follow Lucifer in rebellion againstgod.
Because they know god --that He is the only god-- the angels can't beredeemed once they reject god's rule over them. They already have perfectknowledge of the Creator of all things.
Man was not given the knowledge of good and evil in the beginning. Rather,he, having been also created with free-will, chose wrongly based apparently,at least in part, upon his lack of full understanding. Man, therefore,has a means of Redemption available to him through Christ's shed blood,because he (man) must come to the knowledge that he needs salvation. Manneeds salvation because he disobeyed God and was lost, or fell fromfellowship with god, when he partook of the forbidden tree of knowledge ofgood and evil, and his nature became sinful.