Whenever I roast a chicken, or when I cut one up and have all the spare parts available, I make stock. Sometimes I freeze it for later use. Sometimes I make gravy. Sometimes I use it to for the cooking liquid for rice. And quite often, I make soup.
If you don't happen to have home made chicken stock hanging around waiting to be used, you can buy ready-made stock. If you do that, be sure to taste your soup before you add any salt, since some brands can be quite salty.
You could also use water for your liquid and add Better Than Bullion for the chicken flavor. Rather than a stock, it's a paste that comes in a small jar. I usually have some on hand for the times when I need just a little flavoring and don't want to reach into the freezer for a larger quantity of home made stock.
The thing to remember about chicken breasts is that you don't want to cook them too long, or they tend to dry out. And yes, they can dry out even when they're cooking in a liquid. They secret here is that the breast is added at the end of the cooking time, so they poach gently.
As far as how large or small to cut the vegetables, there's wiggle room for personal preferences, but consider that you're not making stew - you're making soup. You want to be able to not only fit the items on a spoon, it would be nice if you can pick up a few different things at a time and get them into your mouth without having to unhinge your jaw.
The chicken breast I used came from Frontiere Natural Meats here in Longmont. It was boneless and skinless, so all I had to do was cut it into cubes.
Chicken Vegetable Noodle Soup
4 quarts chicken stock
1 onion, peeled and diced
6 finger-thick carrots or 3 larger carrots, peeled and sliced
1 stalk celery, sliced
2 potatoes, peeled and cut into spoon-friendly cubes
1 14- to 15-ounce can diced or whole tomatoes (smashed to break them up) or about 2 cups fresh peeled tomatoes, diced
1 tablespoon lemon juice (or to taste)
Kernels from 3 ears of corn
Salt and pepper, to taste
Large hand full of dry noodles
1 chicken breast, cut into spoon-friendly cubes
Put the chicken stock, onion, carrots, celery, potatoes, tomatoes, and lemon juice in a stockpot or other large cooking vessel. Heat to a boil, then lower to a simmer. Cook until the vegetables are all as tender as you like. Add the corn.
Taste for seasoning and add salt and pepper, to taste.
Heat the soup to a boil again and add the noodles of your choice. You can add more or less, depending on how much you like noodles, but keep in mind that they will expand, and they will absorb some of the soup stock, so don't get carried away - you want soup and not a pasta dish, right?
I used kluski noodles, but pretty much any noodle you like will work. Cooking time will vary depending on the noodle chosen. Cook until the noodles are done to you liking, then add the chicken and cover the pot, and turn off the heat. After a few minutes (depending on the size of the chicken cubes, of course) the chicken will be completely cooked and the soup will be ready to serve. Check one of the chicken cubes to be sure - just remove one and cut it in half.
Disclaimer: I occasionally receive products from Frontiere Natural Meats at no cost to me for my use in creating blog posts.