Season chicken with garlic powder, onion powder, oregano, thyme, salt, pepper, and oil. Mix well to coat evenly.
Heat a large pan over medium heat and pan-fry the chicken for 5 minutes per side, until golden and cooked through. Remove from the pan and set aside.
In the same pan, melt butter. Add green onion whites, mushrooms, and garlic. Sauté for 3–4 minutes, until mushrooms are softened and lightly golden.
Pour in chicken stock and heavy cream. Stir well, then add miso paste and mix until fully dissolved. Bring to a gentle simmer.
Add the chicken back into the pan. Simmer for 3–4 minutes, spooning the sauce over the chicken until everything is rich and creamy.
Serve hot with rice, pasta, or crusty bread.
