Cut chicken breast into thin, bite-sized slices. Peel and slice carrot. Chop celery and potato into small pieces. Finely dice onion.
In a large pot, add chicken, veggies, broth, and seasonings and bring the pot to a boil over medium-high heat. Cover and reduce heat to simmer for 10 minutes.
Meanwhile, mix together the dumpling dough. Stir together flour, baking powder, salt, and garlic powder. Then add milk and olive oil and mix until combined.
After ten minutes, add 1 cup of frozen peas and return to a boil over medium-high heat. Once at a rolling boil, drop teaspoonfuls of dumpling dough into the boiling water until all dough is used.
Cover the pot and reduce heat to medium, keeping it at a boil without bubbling over. Keep closed for 15 minutes while dumplings cook/steam.
After 15 minutes, remove lid and check to make sure veggies, chicken and dumplings are cooked. Dumplings should be cooked in the center rather than doughy. If needed, keep the pot boiling for a few more minutes until all parts are cooked to your liking.