Heat a wok over medium-high heat (you can also use a very large sauté pan). Add the oil, garlic, and galangal and cook about 1 minute, until fragrant.

Add the chicken and cook, stirring frequently, until thoroughly done, about 5 to 8 minutes.

Add the mushrooms, bamboo shoots, and water chestnuts. Cook 3 to 4 more minutes, stirring frequently, until mushrooms are mostly cooked.

Add the bok choy, cashews, and ½ cup of the stock. Cook until the greens start to wilt, about 3 to 4 minutes, stirring frequently.

In a small bowl, mix arrowroot powder, vinegar, and salt with the remaining ½ cup of stock to make a slurry. Add the slurry to the wok and stir until thickened, about 2 more minutes. Taste and add more salt, as needed, before serving.

Serve over rice or cauliflower rice.