Preheat oven to 375 degrees Fahrenheit.
In a large bowl, combine chicken and potatoes. Drizzle with 1 tablespoon olive oil, toss to coat, and season with salt, pepper, and Italian seasoning.
Heat butter in a large skillet over medium heat. Add remaining 1 tablespoon olive oil and stir.
Place chicken on one side of the skillet and potatoes on the other. Cook undisturbed for 3-4 minutes, flip chicken and cook 3-4 more minutes until both are browned.
Transfer chicken and potatoes to a plate and cover to keep warm.
In the same skillet, melt butter over medium heat. Stir in garlic and cook for 1 minute until fragrant.
Add chicken broth and Dijon mustard. Whisk in heavy cream, salt, and black pepper.
Return chicken and potatoes to the skillet. Toss to coat with sauce.
Transfer skillet to oven and bake for 15-20 minutes, until chicken is cooked through and potatoes are tender.
Serve chicken and potatoes with sauce spooned over top, garnished with cracked black pepper and fresh herbs if desired.