Bavinck makes the interesting, Augustinian, and important point that sin can never become our essence because it is not a substance: “it does indeed inhabit and infect all of us, but it is not and cannot be the essence of our humanity. Also, after the fall, we human beings remain humans. We have retained our reason, conscience, and will, can therefore control our lower sensual drives and inclinations, and thus force them in the direction of virtue.”
Talking of “sinful nature” is thus ambiguous. Sinners have depraved, rebellious, infected, dead, but still human nature.