Start by cubing the chicken breasts into bite-sized pieces and season them with garlic powder, salt, and pepper.

Sprinkle flour over the seasoned chicken pieces and toss gently to coat.

In a large skillet, heat olive oil and butter, then add the flour-coated chicken and cook for 5-7 minutes until golden brown.

In the same skillet, add chopped onions and sliced mushrooms, sauté for 5 minutes until onions are translucent.

Stir in minced garlic and Dijon mustard and sauté for an additional minute.

Pour in chicken broth, scraping any browned bits from the skillet and simmer for a few minutes.

Return the browned chicken to the skillet and stir gently to coat.

Add sour cream and fold gently into the sauce until combined.

Serve hot over egg noodles, mashed potatoes, or rice.