Cheesy Broccoli-Potato Soup

2 cups chicken broth
1/3 cup chopped onions
1 package (10 ounces) frozen chopped broccoli
1 1/3 cups mashed potatoes (dry)
2 cups cut-up cooked chicken
2 cups shredded Swiss cheese (8 ounces)
2 cups milk
1/2 teaspoon salt

1. Heat broth, onion and frozen broccoli to boiling in 3-quart saucepan. Reduce heat; cover and simmer 5 minutes, stirring occasionally.
2. Stir in potatoes until well blended; stir in remaining ingredients.
3. Heat over low heat about 5 minutes, stirring occasionally, until hot and cheese is melted.