Rinse chicken, pat dry, and cut into 1-inch chunks. In a bowl, mix flour, salt, chili flakes, and five spice. Add chicken pieces and mix to coat.
Pour oil into a 4- to 5-quart pan over medium-high heat. Add chicken mixture, garlic, and ginger. Stir frequently until chicken is cooked on the outside but still pink in the center (cut to test), about 3 minutes. Add coconut milk and broth and bring to a simmer. Adjust heat to maintain a simmer, cover, and cook to blend flavors, about 5 minutes.
Stir in spinach, corn, tomatoes, water chestnuts, green onions, and lime juice and cook, stirring often, until spinach is wilted, about 3 minutes. Sprinkle with cilantro before serving from pan.