Nature is signed a bit like outdoors or out: first, make your non-dominant hand into a cup. Then starting with your dominant hand in the form of the ASL flat letter O sign inside the cup, move your flat 'O' hand outside the cup a short distance. Do this twice to sign nature.
Teach your toddler the nature sign when you are outdoors and appreciating the beauty of nature's flora and fauna, or if you are teaching them the different examples of nature through their picture books or learning apps.
This is a useful flash card taught best in conjunction with animal, plant, and land and sea flash cards.