Preheat oven to high broil. Places chiles on a baking sheet lined with foil and sprayed with cooking spray. Broil 3-4 minutes until peppers begin to blacken, then turn over and continue to cook 1-2 minutes longer. Remove from oven, allow to cool slightly, then remove stems and seeds, dice, and set aside.
Heat sesame oil in a large pan over medium heat. Saute red and green bell peppers, snow peas, and garlic 2-3 minutes. Add chicken and continue to cook, stirring throughout, until chicken is cooked through.
In a bowl combine soy sauce, 3/4 cup water, brown sugar, and crushed red pepper flakes and whisk until smooth. Add to pan and stir to coat chicken and veggies.
In a small bowl whisk together corn starch and 2 tablespoons cold water. Bring contents of pan to a boil, add corn starch mixture and stir until thickened. Reduce heat, stir in roasted chiles and simmer 5 minutes. Garnish with peanuts and serve with steamed or fried rice if desired.