Heat the olive oil on SAUTE mode of your electric pressure cooker with the lid off. Add the onion, garlic, celery and carrots and stir. Cook the veggies for about 5 minutes, or until the onion is translucent and the garlic is fragrant.
Add the potatoes, diced tomatoes, beans, broth. Lay the chicken on top of the veggies and add the oregano and red pepper flakes over the chicken. Season everything with salt and pepper.
Secure the lid and select MANUAL mode. Cook at high pressure for 10 minutes. Use a natural release when the cooking is complete (this takes 10 - 15 minutes). Remove the chicken breast and shred. Add the balsamic vinegar and stir everything together. Return the chicken to the stew, stir and serve immediately.
You can use the Quick Release option on your electric pressure cooker, if you are pressed for time. You can also use the SOUP setting, if applicable, for this recipe. Set the timer to 10 minutes using this setting and proceed with the recipe.