Yea, you actually can make a delicious soup with nettles as the main ingredient. Just pick the top leaves (or when the plants are really small you can take more) about four cups and boil them quickly. Change water (approximately 3 cups) and add two vegetable stock cubes. Bring it to a boil and then mix it. Taste it to see if you need more salt.
I always poach a couple of eggs in the soup (one for each serving), and some like to add strips of chicken. Serve it with some sour cream and sprinkle bacon over.