Thai Chicken and Pineapple Stir Fry

Name: Thai Chicken and Pineapple Stir Fry
Prep time: 10 min
Cook time: 15 min
Total time: 25 min
Cuisine: Thai, Asian
Ingredients: 1 lb boneless skinless chicken breast (cut into 1-inch cubes); 1 tbsp fish sauce; 2 tbsp cornstarch; 1 tbsp oil (divided); 1 tsp minced garlic; 1 tsp minced ginger; 2 cups cubed assorted colors bell peppers (1/2-inch cubes); 1 red chili pepper (chopped (optional or to taste)); 1 cup fresh pineapple chunks; 1/3 cup Thai sweet chili sauce; cilantro leaves (for garnish)