In a dry nonstick pan on medium-low heat, gently roast cashews for 5-7 minutes or until just beginning to brown. Remove to a bowl and set aside.
Roughly chop onion, yellow squash, and bell peppers. Rinse and set aside.
Slice chicken into roughly bite-sized pieces, about 1-inch. Add to a small bowl and toss with minced garlic, minced ginger, sesame oil, white pepper, and black pepper. Set aside.
In a small bowl, combine all sauce ingredients (soy sauce, oyster sauce, hoisin sauce, honey, rice vinegar, garlic powder, gochugaru, cornstarch dissolved in water) and stir to combine. Set aside.
Heat wok to medium-high/high. When hot, add chicken to wok and immediately begin stirring. Cook for 5-7 minutes, or until chicken has begun to brown on the edges. Remove from wok and set aside.
Add chopped vegetables and whole mushrooms to the still-hot wok and immediately begin stirring. Cook for 3-5 minutes, or until vegetables have begun to brighten in color and soften.
Add sauce mixture and cook for an additional 2-3 minutes, or until sauce has begun to thicken.
Return chicken to the wok and add roasted cashews. Toss to coat, and cook for an additional 2-3 minutes.
Remove from heat and add lime juice and lime zest. Stir to incorporate.
Serve over white rice, topped with additional cashews, lime juice, and sesame seeds.