Cut the chicken into pieces and place in a large bowl. Sprinkle with the flour, garlic powder, onion powder, smoked paprika, salt, and pepper. Toss to coat evenly.

Heat a large skillet over medium-high heat. Add 2 tablespoons of the oil. When the oil is hot, add half of the chicken to the pan and let it cook for 2-3 minutes per side. Leave it alone for the first 2-3 minutes so it can brown and sear on one side before turning the pieces using tongs. Once the chicken is cooked, transfer to a plate and repeat with the remaining chicken, adding a little additional oil if the pan gets dry. Set chicken aside and keep warm.

Add the butter to the hot pan. Let it melt, then add the onion and mushrooms. Saute for 6-8 minutes until softened and most of the liquid has cooked off.

Add the Worcestershire sauce, mustard, and garlic. Cook and stir for another 30-60 seconds, then add in the broth, using a wooden spatula to scrape up any browned bits from the bottom of the pan. This is called deglazing the pan and the browned bits are called "fond". There is a ton of flavor there that really adds to the dish.

Return the chicken to the pan and continue to cook for 2-3 minutes, stirring occasionally, until everything is hot. The bit of flour that the chicken was coated with will slightly thicken the sauce so it is silky instead of runny.

Stir in the sour cream, then remove from the heat before the sauce starts to bubble, which can cause the sour cream to curdle. Season with additional salt and pepper, if needed, then serve with egg noodles, mashed potatoes, or rice.