Slice the chicken crosswise. In a bowl, lightly beat the egg white. Stir in the chicken, 1 tbsp. oil, 1 1/2 tbsp. cornstarch, 1 tsp. rice wine vinegar and 3/4 tsp. salt. Cover; chill for 30 minutes.
Place the rice in a medium saucepan. Fill the pan halfway with cool water and rub the rice with your fingers. Drain in a mesh strainer. Repeat twice to clean the rice.
Return the rice to the saucepan, add 1 1/4 cups cold water and bring to a boil. Reduce the heat, cover and simmer for 17 minutes. Remove from the heat and let sit, covered.
Make the sauce: In a small bowl, stir or whisk together the broth, the remaining 1/2 tsp. cornstarch and 2 tsp. rice wine vinegar, 3/4 tsp. salt and 1/4 tsp. pepper.
Fill a large saucepan with 4 cups water and bring to a boil. Using a large slotted spoon, add the chicken and stir for 1 minute; drain in a colander.
Trim the snow peas. Preheat a wok over high heat for 1 minute. Add the remaining 3 tbsp. oil, the ginger and garlic; stir-fry for 1 minute. Add the snow peas and stir-fry for 1 minute.
Add the chicken to the wok with the spatula. Stir the sauce again and pour over the chicken.
Cook, stirring, until the sauce thickens, the chicken is cooked and the peas are crisp-tender, about 3 minutes.
Fluff the rice and spoon onto plates. Spoon the chicken mixture on top. Chop the cashews; sprinkle on top.