Add the chicken thighs to a mixing bowl and toss with Italian seasoning, salt, onion powder, paprika, and black pepper.
To a hot, oiled pan, add seasoned chicken thighs and cook on each side for about 5 minutes. Transfer the cooked chicken to a plate and set aside. Do not wipe the pan out.
Reduce stovetop heat and scrape up any browned bits from the bottom of the pan. Add butter and allow to melt. Add minced garlic and cook until fragrant before adding mushrooms. Sprinkle in ground thyme. Cook mushrooms until golden, then gently stir to cook the other side.
Add sun-dried tomatoes and cook for about 30 seconds before pouring in heavy cream and chicken stock, cooking until a sauce begins to form. Stir in the grated Parmesan and allow it to melt.
Return the cooked chicken to the pan and spoon the sauce atop the chicken. Garnish then serve.