Bring a large pot of water to boil, and cook shell pasta according to package.
Preheat oven to 400 degrees F. Season chicken, in a medium bowl, on both sides with salt, pepper, 1 Tbsp. rosemary and 1 Tbsp. thyme. Heat the olive oil and fresh garlic over medium heat in a large skillet. Add chicken, to the hot oil and cook for about 10 minutes or until no longer pink.
Remove chicken from skillet and set aside. Add mushrooms to skillet and turn heat to medium-high; cook stirring occasionally for 4 minutes. Mushrooms should begin to sweat. Add flour to skillet, stirring to coat. Stir in chicken broth, wine, and mustard. Cook and stir until thickened and bubbly, ~5 minutes.
In a Pyrex or oven safe casserole dish, combine cooked pasta, cubed chicken, remaining herbs and mushroom sauce into the dish and mix well. Cook in oven for 15-20 minutes, and enjoy!