2 tablespoons olive oil
1 onion, diced
2 pounds chicken thigh meat, cut into bite-sized pieces
8 ounces cremini or button mushrooms, quartered (halved if large)
4 garlic cloves, minced
1 bay leaf
1 teaspoon kosher salt
1/2 teaspoon black pepper
1/2 cup chicken broth
1 teaspoon Dijon mustard
2 tablespoons cornstarch mixed with 2 tablespoons cold water
1/3 cup sour cream
Heat the oil in the Instant Pot, using the sauté function.
Add the onions to the pot and cook, stirring occasionally, until softened, about 5 minutes.
Add the chicken, mushrooms, garlic, bay leaf, salt, pepper, broth and mustard, and stir to mix. Turn the sauté function off by pressing the keep warm/cancel button.
Close the lid and turn the valve to the sealing position. Choose high pressure and set the timer for 15 minutes.
Once the cooking time is up, let the pressure release naturally for 5 minutes, then quick release any remaining pressure.
Remove the lid and turn on the sauté function again. Add the cornstarch-and-water mixture and cook, stirring, until the sauce thickens, about 2 minutes.
Just before serving, ladle a bit of the broth out of the pot and stir it into the sour cream, then stir the sour cream mixture into the pot. Serve hot.