Dice the chicken breast into bite-sized pieces and finely chop the carrots, celery, and onion.
In a small pot, heat the olive oil over medium heat and sauté the carrots, celery, and onion until softened, about 5 minutes.
Pour in the chicken broth and add the sea salt, black pepper, and garlic powder. Bring the mixture to a gentle simmer.
Add the diced chicken to the simmering broth and cook for 3-4 minutes until nearly opaque.
In a small bowl, whisk together the whole wheat flour, baking powder, and dried thyme. Stir in the Greek yogurt and water until a thick dough forms.
Drop small spoonfuls of the dough (about 1 tablespoon each) onto the surface of the simmering soup.
Cover the pot with a tight-fitting lid and reduce heat to low. Steam for 8-10 minutes without lifting the lid until the dumplings are fluffy and the chicken is cooked through.
Ladle the chicken, vegetables, and dumplings into a bowl and serve immediately.