Preheat oven to 200ºC (390ºF). Brush pork with hoisin and place on a tray. Roast for 10 minutes each side or until cooked through. Set aside and keep warm. Allow to rest for 5 minutes before slicing.
Heat oil in a saucepan over medium heat. Add ginger, garlic and five-spice and cook for 1 minute. Chop the coriander stalks and add to the pan with the stock and soy. Bring to the boil and cook for 5 minutes. Remove and discard ginger, garlic and stalks. Add noodles to the broth and cook for 5 minutes. Add the bok choy and cook for a further 2 minutes.
Divide noodles, bok choy, broth and pork between bowls. Top with coriander and green onion, and serve with chilli. Serves 2.