Pour the chicken broth into the Instant Pot and add the herbs de provence, then place the trivet inside. Place the chicken on top of the trivet, breast side up.

Secure the lid and set the Pressure Release to Sealing. Select the [Poultry] setting and adjust the time to 20 minutes at high pressure.

Let the pressure release naturally for at least 15 minutes, then move the Pressure Release to Venting to release any remaining steam (you can also just let the pressure release naturally, which takes about 25 minutes).

Open the pot and use a pair of heat proof mitts to lift the chicken out of the pot with the trivet. Transfer the chicken to a dish or carving board to cool. Pour the broth into a fat separator or other liquid measuring cup.

Preheat the oven to 425ºF.

Press the [Keep Warm/Cancel] button to reset the cooking program, then select the [Sauté] setting and melt two tablespoons of the butter in the Instant Pot. Stir in the diced onion, carrots, celery, salt, and pepper. Cover the pot with its other, glass lid (or any regular saucepan lid that fits) and let the vegetables sweat, covered, for 10 minutes.

While the vegetables are cooking, remove the meat from the chicken. Tear or chop the meat into bite-sized pieces, and discard the skin, bones, and cartilage. If this takes you longer than the 10 minutes required to cook the vegetables, press the [Keep Warm/Cancel] button to turn off the pot so they don’t overcook or burn.

After the vegetables have been sweating for 10 minutes, uncover the pot. If you’ve turned off the pot, select the [Sauté] setting once again. Stir in the flour, then the wine. Let the wine simmer for 3 minutes, just until it has mostly evaporated.

Whisk in two cups of the reserved cooking liquid. Let it come to a boil and thicken for about a minute.

When the liquid has thickened, press the [Keep Warm/Cancel] button to turn off the Instant Pot once again. Stir in the cooked vegetables, chicken, frozen peas, and ground pepper.

Transfer the filling mixture from the Instant Pot to a large skillet.

Melt the remaining two tablespoons of butter and toss it with the breadcrumbs. Sprinkle the breadcrumbs over the filling in the skillet.

Bake the pot pie until the breadcrumbs are well-browned, about 5-10 minutes.