IF you're Born Again of the Holy Spirit by FAITH in the perfect SIN OFFERING of Jesus on the cross (Eph 2:8,9) then you HAVE been cleansed of all your sin - assuming that when AS A CHRISTIAN you sin, you confess it (1 John 1:9) so it can be cleansed.
Acts 2:38
38 Then Peter said to them, “Repent, and let every one of you be baptized in the name of Jesus Christ for the remission of sins; and you shall receive the gift of the Holy Spirit.
Bob, how many times must you "Repent" and how many times must you be baptized in water to receive the gift of the Holy Spirit? And what does the Holy Spirit do in us? Romans 6:6-7
6 knowing this, that our old man was crucified with Him, that the body of sin might be done away with, that we should no longer be slaves of sin. 7 For he who has died has been freed from sin.
It is exactly the same many times we must confess our sins in 1 John 1:9 - ONCE to become a born again Christian, and free from sin.
You never HAD a "Sin nature" all you have is a "HUMAN NATURE" which still functions as it always has, and you're still tempted according to James 1 - and sometimes you let the temptations "conceive" and become sinful acts - just like the rest of us.
Two natures? Scripture is full of why Jesus came - to free us from sin - what separated us from God in the first place. What most denominations do not get is that starting with the first separation from 1st century teaching, the RCC, and continuing through the Reformation, we have either the divine nature of God and a human nature that chooses righteousness from our own will out of obedience to God, or the carnal sinful nature and human nature, but it struggles between what is the law of God and our carnal desires, which the first is free from. We do NOT HAVE BOTH.