In a medium saucepan, melt 2 tablespoons butter over medium heat. Add the onion and 1/4 teaspoon each salt and pepper and cook, stirring, until golden, about 5 minutes. Stir in the rice and 3 cups chicken broth and bring to a boil. Lower the heat, cover and cook until tender, about 20 minutes.
Meanwhile, in a large skillet, cook the sausage, breaking it up, over medium heat until no longer pink, about 7 minutes. Using a slotted spoon, transfer the sausage to a plate. Add the zucchini to the skillet and cook until tender, about 4 minutes. Return the sausage to the skillet, add the remaining 1 cup chicken broth and 1/2 cup water and cook, stirring, until heated through, about 2 minutes.
Stir in the rice along with 1/2 cup Parmesan, the parsley and the remaining 2 tablespoons butter. Top with the remaining 1/4 cup Parmesan and the pine nuts.