Add chicken broth, celery, and carrots to a large saucepan.
Bring to a boil.
Add the chicken and the pasta to the pan and reduce heat to a slow boil.
Continue to cook for 10 to 12 minutes or until the pasta is done.
Remove from the heat and cover with a lid and allow to sit for 10 to 15 minutes or until the pasta is soaked up most of the liquid.
Remove the lid and stir. Serve while hot.
Notes
Uncooked chicken can be used, simmer it in the broth until 160°F. Remove from the broth and allow it to cool. Once cool, dice or shred 3 cups of chicken meat.
Slice carrots to about 1/4" thick so that they will cook in the same amount of time as the pasta. Thicker sliced vegetables will require 5 to minutes of cooking before adding the pasta.
Do not add additional pasta, the pasta will swell and absorb most of the liquid.