Set the instant pot on SAUTE function, let it heat up. Add olive oil (or butter + olive oil) once the butter melts add onion, carrots, and celery, cook until the veggies start to soften about 3-4 minutes. Add garlic and sauté it for a few seconds.
Add chicken breasts, potatoes, mixed Italian seasoning, salt, and pepper; give a mix. Next, add chicken broth. Mix and let it bubble for a few minutes.
Take the dough out of the fridge. Scoop one tablespoon of dumpling dough and place it on top.
Close the lid and seal pressure valve. Cook at high pressure for 10 minutes.
Release naturally for 10 minutes.
Carefully take the chicken and dumplings out with the help of tongs and shred. Set aside.
Set the instant pot on sauté function.
Add frozen peas and stir to combine. Next, add the shredded chicken back to the Instant Pot.
Make a slurry by mixing 1 tablespoon of cornstarch with 2 tablespoons of water.
Once the liquid starts to bubble add the cornstarch slurry and simmer until the broth has thickened.
Cancel and return the dumplings to the pot just before serving.