Romans 6:6
New American Standard Bible (NASB)
6 knowing this, that our old self was crucified with Him, in order that our body of sin might be done away with, so that we would no longer be slaves to sin;
old man without knowledge of God Not born again. Old father, old nature, old creature.
John 8:44
New American Standard Bible (NASB)
44 You are of your father the devil, and you want to do the desires of your father. He was a murderer from the beginning, and does not stand in the truth because there is no truth in him. Whenever he speaks a lie, he speaks from his own nature, for he is a liar and the father of lies.
Ephesians 2:1-3
New American Standard Bible (NASB)
Made Alive in Christ
2 And you were dead in your trespasses and sins, 2 in which you formerly walked according to the course of this world, according to the prince of the power of the air, of the spirit that is now working in the sons of disobedience. 3 Among them we too all formerly lived in the lusts of our flesh, indulging the desires of the flesh and of the mind, and were by nature children of wrath, even as the rest. (were past tense by nature)
Born again believer. New Father, new nature, new creature.
1 John 3:1
New American Standard Bible (NASB)
Children of God Love One Another
3 See how great a love the Father has bestowed on us, that we would be called children of God; and such we are. For this reason the world does not know us, because it did not know Him.
2 Peter 1:4
New American Standard Bible (NASB)
4 For by these He has granted to us His precious and magnificent promises, so that by them you may become partakers of the divine nature, having escaped the corruption that is in the world by lust.
It's a matter, very much like separating law and grace. There is the very nature of a person and there is the mind of the person that needs to be renew.
I do not believe someone can have two natures but I do believe that the new nature will need to do battle with the flesh/mind.
Paul equates the flesh to the mind not to the spirit. Paul's nature was that of the divine was it not and yet he battled his flesh/mind.