Cheesy Broccoli-Potato Soup

2 cups chicken broth
⅓ cup chopped onion
1 package (10 oz) frozen chopped broccoli
1 ⅓ cups instant potatoes (dry)
2 cups cut-up cooked chicken
2 cups shredded Swiss cheese (8 oz) (you can actually use any type of cheese, I have substituted whatever I have around - mozzarella, cheddar, colby/jack)
2 cups milk
½ tsp salt

Heat broth, onion and frozen broccoli to boiling in 3-quart saucepan. Reduce heat; cover and simmer 5 minutes, stirring occasionally. Stir in potatoes until well blended; stir in remaining ingredients. Heat over low heat about 5 minutes, stirring occasionally, until hot and cheese is melted. Makes 6 servings, about 1 ⅓ cups each.