Preheat the oven to 300°F. Place the 1 cup cashews on a baking sheet in a single layer. Toast in the oven until fragrant, stirring or shaking pan once, about 15 minutes.
Trim any fat from 1 1/2 pounds boneless skinless chicken breast and cut into bite sized pieces.
Slice 8 green onions in half (white vs green) and separate. Cut into one inch pieces, but keep the whites separate from the greens.
Heat half of the 2 tablespoons oil in a wok or large saute pan over high heat. When oil is almost at its smoke point, add half of the chicken. Stir only to prevent burning and cook until golden brown. Transfer to a plate. Add remaining oil and once oil is hot, add remaining chicken along with the white sections of the green onion. Allow to brown while occasionally stirring. During last minute or so, add the 1 tablespoon garlic. Once this half of the chicken has browned, add first batch back to the wok and reduce heat to medium.
Add 2 tablespoons rice vinegar, stir, and cook until evaporated. Add 4 tablespoons hoisin sauce, 1 tablespoon soy sauce, and 1 tablespoon fish sauce. Stir well and allow to cook until all chicken pieces are fully cooked through. This shouldn't take more than a minute.
Turn off heat and stir in roasted cashew pieces, remaining green onions, and 1/2 teaspoon toasted sesame oil.
Notes
Serving suggestions: Serve this chicken with cashew nuts recipe on a bed of steamed short grain rice. Add a little more green to your plate with some steamed broccoli or sauteed peppers and onions and you'll have a complete meal.
Toasting the cashews: Raw cashews that get toasted in the oven work really well in this recipe. Raw nuts are a bit sweet with fantastic texture and toasting them enhances their flavor and adds to their crunchy texture. Pre-roasted nuts can be used but they will not taste as good.
Storage and reheating: Leftovers can be stored in an air tight container in the refrigerator for 3-5 days. Reheat in microwave on 50% power in one minute increments until heated through or on the stove over low heat.