1. Turn on the Instant Pot and select the sauté function. Add a bit of oil and sauté the onions, carrots, and celery until softened.
2. Add the diced chicken and cook until browned.
3. Pour in the chicken broth, salt, and pepper. Stir well.
4. Lock the lid and set the Instant Pot to manual high pressure for 10 minutes.
5. While the chicken is cooking, prepare the dumplings. In a mixing bowl, combine flour, baking powder, and salt. Stir in milk and melted butter until just combined.
6. Once the cooking time is up, perform a quick release. Open the lid and stir in the frozen peas.
7. Drop spoonfuls of the dumpling batter on top of the chicken mixture. Close the lid and set the Instant Pot to manual high pressure for another 5 minutes.
8. Perform a quick release again. Serve hot and enjoy!