1. Season and coat the chicken: Season the chicken pieces with garlic powder, salt, and black pepper. Lightly coat each piece in flour, shaking off any excess.

2. Brown the chicken: Heat 2 tablespoon of olive oil in a deep skillet over medium-high heat. Brown half the chicken for 3-4 minutes per side until golden and cooked through, then transfer to a plate. Repeat with the remaining chicken, adding a bit more oil if the pan becomes dry.

3. Sauté the mushrooms and onions: Reduce the heat to medium and add 1 tablespoon of olive oil and the butter to the same skillet. Add the sliced mushrooms and chopped onion, and cook for 6-8 minutes, stirring occasionally, until the mushrooms release their liquid and are nicely browned.

4. Build the flavor: Stir in the Dijon mustard, Worcestershire sauce, and minced garlic. Cook for about 1 minute, until fragrant.

5. Deglaze and simmer: Pour in the chicken broth, scraping up any browned bits from the bottom of the pan. Return the browned chicken and any juices to the skillet and simmer for about 2 minutes.

6. Finish with sour cream: Reduce the heat to low and stir in the sour cream until smooth and creamy. Be careful not to let it boil.

7. Taste and adjust: Taste the Rich Chicken Stroganoff and season with additional salt and pepper as needed.

8. Serve and enjoy: Serve hot over egg noodles, mashed potatoes, rice, or pasta.