Paul said in the flesh dwells no good thing, and the Spirit and the flesh are contrary to each other.
Jesus had a sin nature according to the flesh, but He is God manifest in the flesh, so He was always led of the Spirit.
Which the Bible says if a person hates sin, and does not want sin, by the Spirit they can abstain from sin, for a Spirit led life will not fulfill the lusts of the flesh, for they have crucified the flesh with the affections and lusts, and show the ways of the Spirit which there are no ways of the flesh there.
So even a saint can abstain from sin by the Spirit, and they still have a sin nature according to the flesh, but they can sin if they want to sin, but Jesus was always led of the Spirit so He could not sin, but He was made like us for He had to be human like us for Him to qualify as the Savior, for only a sinless man can reconcile mankind to God.
They say we inherit Adam's sin nature, but I say it is choice that causes the dilemma.
When Adam and Eve ate from the tree they then had a choice between good and evil, so all their offspring has a choice between good and evil, so we are born not knowing God, and will do evil before we come to God and repent, so all are sinners and come short of the glory of God.
But we are born innocent without sin in our life, and a clean record, which the Bible says that the angels always behold the face of the Father for the little ones that have not come to the age of accountability, which they are protected spiritually.
But because of choice we are born not knowing God, so we will do evil before we come to God and repent.
Jesus had to of had a sin nature as us, and be made like us, for Him to qualify as fully human so salvation could be effective, but He is God manifest in flesh so He was sinless always led of the Spirit, but His flesh wanted to sin, but He did not have the desire to heed the flesh being God.
Jesus being born of Mary without a human father does not make Him less human, for God did create all things, and can heal, so He can cause Jesus to be completely human that did not have a human father.