In a small bowl, combine corn starch, broth, peanut butter, miso, soy sauce, vinegar, ginger, sriracha, and pepper. Set aside.

Add sesame oil to a wok or large sauté pan and place over high heat. Once hot starts to smoke, add chicken, stir frying until cooked through. Transfer chicken to a plate.

Stir fry vegetables, in batches, adding more oil if necessary, until vegetables are lightly browned.

Add chicken and vegetables back to the pan and add psauce, stirring constantly until thickened.

Transfer chicken and vegetables to a platter and garnish. Serve with lo mein noodles, rice, or in lettuce cups.