A hot pot is a stewlike mixture of meat and vegetables in a savory broth. Here, the dish is given Asian accents with bok choy, soy sauce, sesame oil, and rice vinegar.
Place mushrooms in a small bowl; add 2 cups warm water. Let soak until softened, about 30 minutes. Drain in a sieve lined with a paper towel or coffee filter, reserving liquid. With a paring knife, remove stems; discard. Thinly slice caps.
In a large stockpot, heat canola oil over medium heat. Cook garlic and crushed red pepper, stirring, until fragrant, about 30 seconds. Add mushrooms; cook, stirring, until golden brown, about 5 minutes. Add broth, soy sauce, reserved liquid, and 1 cup water; bring to a boil.
Add chicken; reduce to a simmer. Cover; cook until chicken is cooked through, 8 to 10 minutes. Remove chicken; let cool, then shred meat.
Add bok-choy stems and bell pepper to pot; cook until tender, about 2 minutes. Stir in vinegar, sesame oil, and cornstarch mixture. Bring to a boil; cook 1 minute. Stir in bok-choy greens. Ladle into bowls, and top with shredded chicken.