Bacon and Baked Potato Soup

1 tablespoon butter or margarine
1/4 cup chopped onion
1/4 cup chopped celery
1 (14 1/2 ounce) can chicken broth
1 1/4 cups milk
2 medium baking potatoes, baked and cut into 1/2-inch cubes
1/4 teaspoon salt
1/4 teaspoon pepper
8 slices bacon, crisply cooked, crumbled and divided
2 tablespoons green onions, divided
1/4 cup sour cream

Melt butter in heavy saucepan. Add onion and celery; cook and stir until crisp-tender. Add broth, milk, potatoes, salt and pepper; bring just to a boil, stirring constantly. Slightly crush potatoes with spoon. Reduce heat to medium-low; simmer 5 minutes, stirring frequently.

Reserve 2 tablespoons each bacon, cheese and green onions for toppings. Add remaining bacon, cheese, green onion and sour cream to soup just before serving. Cook until cheese is melted, stirring constantly. Serve topped with bacon, cheese and green onions.