In a bowl take chicken and add onion powder, garlic powder, black pepper, and salt, and mix everything.

Heat olive oil in a skillet over medium heat, place the chicken pieces, and cook until crisp, golden, and evenly cooked from the inside. Once done Transfer the chicken onto a plate.

In the same pan add 1 tbsp butter and let it melt, add chopped onions and cook it for 1 minute, once the onion turns soft and lightly brown add in the mushrooms.

Cook mushrooms until golden. Add flour and cook while stirring for 1 minute.

Add a little broth and mix, ensuring there are no lumps, add the remaining broth.

Bring to simmer and stir in sour cream and mustard, once the sauce thickens add salt and black pepper.

Next, add the chicken and simmer it for another 1-2 minutes and turn off the heat.