Cut the chicken into pieces. Put the chicken in a slow cooker, add sliced red peppers, and chopped celery. Pour the sauce (recipe below) over the ingredients in the slow cooker and stir to coat.
Cook on low for 2-4 hours, depending on your slow cooker.
Remove the sauce from the slow cooker and put it into a saucepan. Bring it to a boil over medium heat. In a small bowl, stir together cold water and cornstarch. Slowly add the cornstarch mixture to the saucepan stirring constantly. Cook until thickened. Pour the sauce in the slow cooker and stir to coat the chicken.
Sauté the snow peas in the water chestnuts briefly before adding them to the crockpot, if desired.
Sprinkle with cashews and sliced green onions (or chives) before serving.
Spicy Cashew Chicken Sauce:
Whisk together honey, brown sugar, soy sauce, minced onion, vinegar, sesame oil, olive oil, Sriracha sauce, hoisin sauce, minced garlic, and minced ginger in a small bowl and set aside.