Well,the Greek god of nature is Pan,and Gaea wasnature,so I guess that leaves Persephone.
Demeter, in Greek Mythology, is the Goddess of nature, fertility of the Earth, the seasons, and harvests.
Adiona is a goddess in Greek mythology associated with fertility, motherhood, and the harvest.
Demeter is the goddess of agriculture, but Gaia is the god/titan of the earth.
Pandora was not a Greek goddess, but a mortal woman. Anyway, she was a young lady, probably about 20. She had an inquisitive nature, and physical features are unknown.
In Greek mythology the primal goddess of nature is Physis; however, there are many other goddesses of nature, such as Gaia (Earth), Cybele and Rhea (mountains), Demeter (harvest/farming), Persephone (spring), and Artemis (wilderness). The Horae were seasonal goddesses as well.