In a wok, heat 2 tablespoons of the oil. Add the chicken sausage and stir-fry over high heat, breaking it up, until just cooked through, 3 minutes. Transfer to a plate.

Heat the remaining 3 tablespoons of oil in the wok. Add the garlic and ginger and stir-fry over moderately high heat until golden, 1 1/2 minutes. Off the heat, stir in the snow peas and chiles for 1 minute. Add the orange juice and stir over moderately high heat for 30 seconds. Add the sausage, noodles and stock mixture, season with salt and stir-fry until the sauce is thickened, about 2 minutes. Remove from the heat, stir in the basil and serve.