Of course Jesus never sinned without sin also means had no sin , could not sin , would not sin. Why? because HE did not have the sinful nature Jesus has Devine nature because HE is God . With this line of thinking you do not Believe Jesus is God correct?
I think too if we reflect on what sin is defined as then it becomes much easier to see how the claim Jesus had a sin nature is impossible. The argument that he had a sin nature comes full circle in defeating its own proclamation due to the definition of sin.
If Jesus had a sin nature he would have sinned because he was fully human. If it is argued then that Jesus was fully human with a sin nature but chose not to sin then that would mean we too could accomplish the same. Being he was as has been said in this thread, one of us. Or, one like unto us. And that would then have made his birth purpose moot.
If Jesus was divine he could not sin because divinity precludes unrighteousness.