1. Peel and finely chop garlic and ginger. Drain and rinse bamboo shoots and water chestnuts. Chop chicken into ½ inch pieces.
2. Heat a wok over medium-high heat (you can also use a very large sauté pan). Add the oil, garlic, and ginger and cook about 1 minute, until fragrant.
3. Add the chicken and cook, stirring frequently, until thoroughly done, about 5-8 minutes.
4. Add the mushrooms, bamboo shoots, and water chestnuts. Cook 3-4 more minutes, stirring frequently, until mushrooms are mostly cooked.
5. Add the bok choy, cashews, and half of the broth. Cook until the greens start to wilt, about 3-4 minutes, stirring frequently.
6. In a small bowl, mix arrowroot powder, vinegar, and salt with the remaining broth to make a slurry.
7. Add the slurry to the wok and stir until thickened, about 2 more minutes. Taste and add more salt, as needed, before serving.