In a small bowl, add all purpose flour and 1 Tbsp chicken stock and whisk to combine. Set aside.
To a large dutch oven or deep bottomed skillet, add 1 ½ Tbsp of olive oil and heat over MED-HIGH. Add chicken pieces to pan, add ¼ tsp EACH kosher salt and black pepper. Cook 5 minutes, until golden brown and cooked through. Remove to a plate.
Add remaining 1 ½ Tbsp of oil to the pan and add sliced mushrooms and onion. Add remaining ½ tsp black pepper, paprika, dried thyme, oregano, and red pepper flakes. Cook mushrooms about 6-7 minutes, until cooked and slightly golden. Add garlic and cook 30 seconds, stirring often so it doesn't burn.
Pour in wine, scraping the bottom of the pan with a wooden spoon to loosen any browned bits of flavor. Cook wine about 2 minutes, or until reduced by about half.
Stir in remaining chicken stock and bring to a simmer. Once simmering, add remaining ¾ tsp salt and egg noodles, stir and cook, uncovered, 8 minutes or until cooked. Stir every so often as the noodles are cooking to prevent sticking.
Pour in chicken stock/flour mixture, stir and cook 1 minute.
Turn off the heat. Add in cooked chicken, sour cream and mustard.
Sprinkle with chopped parsley and serve.
