Cook egg noodles according to package directions.
Heat 1 tablespoon olive oil over medium high heat. Add in finely chopped onion and mushrooms and sauté for about 5 minutes, or until the onions and mushrooms are tender. Remove the veggies from the pan and set aside.
Melt 1 tablespoon butter over medium-high heat. Add in chicken chunks and cook for 5-7 minutes, until the juices run clear and the chicken is cooked through.
Sprinkle 2 tablespoons flour in the pan.
Add in 1 cup chicken broth, 1 tablespoon worcestershire sauce and 1 tablespoon balsamic vinegar. Stir to combine and whisk out any flour clumps. Bring to a gentle simmer and cook until the sauce starts to thicken, about five minutes.
Add mushrooms and onions back in. Reduce heat to low. Stir in 1/2 cup sour cream or plain Greek yogurt.
Season to taste with additional salt and black pepper.
Garnish with chopped fresh parsley and serve over egg noodles.