The dichotomy between nature and grace is an interesting one. As I understand it, it’s Augustinian in origin – grace held up, or supported nature before the fall, and with the fall, grace was taken away, leaving only nature. Through grace nature is restored. Aquinas developed this in much greater detail.
The Orthodox reject this outright- for the Orthodox the distinction isn’t between nature and grace but between created and uncreated. Grace is an uncreated energy of God that is at work in every part of creation. Where there is creation there is grace.