First, prepare the sauce so you have it ready to use in a couple of minutes. To make the sauce, mix all the ingredients in a medium-sized bowl until combined. Set it aside.
Next, chop the chicken into bite-size pieces. Then, heat 1 tablespoon of olive oil in a large wok. Add chopped chicken and let it cook over medium heat. Turn occasionally until the chicken is golden brown. Once fully cooked, place the chicken on a plate and cover it.
While the chicken is cooking, chop the veggies. First, chop the onion and green bell pepper into bite-size pieces and the green onion into thin slices. Keep some green onion tops to garnish. Then chop garlic into tiny pieces.
Once you remove the chicken from the wok, add another tablespoon of oil. Add the chopped bell pepper, and onion. Stir until onion is translucent and pepper is tender.
Add sliced green onion and chopped garlic. Stir over heat until fragrant.
Add cooked chicken, roasted cashews, and prepared sauce. Stir for one or two minutes to let the chicken and vegetables absorb the flavors.
Serve warm in individual bowls, with or without white rice. Garnish with sesame seeds, chopped green onion tops, and chili flakes.