I've never heard of Nu-Stevia. But stevia itself is not artificial. Its an extract from the leaves of a plant, I believe the plant(s) are related to sunflowers. The extract is much sweeter than sugar. Though I find it has a weird aftertaste. Its been used in some tropical countries for a long time and has been tested in other countries. In Canada, it hasn't been approved as a sugar substitute, thats why you will find it in health food stores.
"Of course its hard, if it were easy everyone would do it. Hard is what makes it great"
-League of Their Own