To make a creamy chicken tortellini soup recipe, first you will need to prepare the ingredients for the soup. First, you'll need the following ingredients: 1 pound chicken breasts, 2 tablespoons butter, 1 teaspoon kosher salt, and 1 tablespoon melted butter. You will also need 2 cups of water. Heat the butter over medium-high heat until it is shimmering. Add the chicken and cook, stirring occasionally, until the meat is no longer pink in the center, 10 to 15 minutes. Remove from the heat and add the remaining ingredients. Cook, tossing, for 2 to 3 minutes, or until thickened. Serve with sour cream and Parmesan cheese.