Combine water, chicken broth, ketchup, soy sauce, honey, garlic, rice vinegar, Sriracha, sesame oil, ginger root, and red pepper flakes for sauce in a medium bowl.

Heat vegetable oil in a wok or large skillet over medium-high heat. Add chicken, and stir-fry until chicken is opaque on all sides, 2 to 3 minutes. Transfer chicken to a plate.

Reduce heat to medium and add the sauce to the wok. Whisk together water and cornstarch in a small bowl and add to the sauce, stirring constantly until the sauce starts to thicken, 3 to 5 minutes. Add chicken back to the wok, stir, and cook until reheated, about 2 minutes.