Pat the chicken thighs dry with a paper towel and season with salt, pepper, garlic powder, and onion powder. Heat olive oil and butter in a skillet over medium-high heat and sear the thighs for 6-7 minutes on each side until golden brown. Remove and set aside.

Reduce heat to medium and add minced garlic to the skillet, sautéing until fragrant. Add flour to make a roux, then gradually whisk in chicken broth, heavy cream, Parmesan, mustard, and dried herbs. Let simmer for 3-4 minutes until thickened.

Return the seared chicken thighs to the skillet, covering them in the sauce. Simmer for 10-15 minutes over low heat, adding lemon juice if desired.

Meanwhile, boil salted water and cook the egg noodles according to package instructions. Drain and toss with a tablespoon of butter.

To serve, place the noodles on plates and top with the creamy chicken and sauce. Garnish with fresh parsley and serve immediately.