Boil the beans in water until crisp cooked. Drain and place in ice water to stop cooking. Drain again and set aside.
Heat peanut oil in a heavy non-stick skillet or wok until very hot. Add the chicken, onion and garlic. Stir-fry for 4 minutes until chicken begins to cook through. Add the lemongrass, fish sauce, sugar substitute, coriander, and turmeric. Stir-fry for another 2 minutes. Add the beans, broth, and oyster sauce. Reduce the heat and simmer until the sauce thickens and chicken is cooked through. Season with pepper.
To serve, mold the rice using a 1/2 cup (small gratin cups and place the chicken around the rice. Garnish with basil. Serve immediately.