Place one cup of oats in a blender and process until well ground. In a large bowl mix together the ground oats, flour, baking powder, baking soda, and salt.
In another large bowl using an electric mixer combine the butter and sugar until smooth. Add egg and vanilla; continue mixing until the mixture is light and fluffy.
Using a large spoon mix in the melted chocolate until well combined. Stir in the flour mixture until moistened and well combined, and then fold in the rest of the rolled oats, chocolate chips, and nuts.
Using about 2 tablespoons of cookie dough at a time, roll the dough into balls and place on a cookie sheet lightly sprayed with cooking spray about 2 inches apart. (Or use parchment paper)
Bake for 14-18 minutes until cookies start to crack and still show some moisture in the cracks.
Let cookies cool on the baking sheet for several minutes, and then place them on a wire rack to cool.