Season chicken pieces with salt and pepper on all sides.
Heat olive oil in a large skillet over medium-high heat. Add chicken and cook until golden brown and cooked through, about 5-7 minutes. Remove chicken from skillet and set aside.
In the same skillet, add onion and bell pepper. Cook until softened, about 3-4 minutes. Add garlic and cook for another minute until fragrant.
Add rice to the skillet and stir for 1 minute to toast slightly.
In a small bowl, whisk together chicken broth, soy sauce, brown sugar, and rice vinegar.
Pour the liquid mixture into the skillet with the rice. Bring to a simmer, then reduce heat to low, cover, and cook for 15-20 minutes until rice is tender and has absorbed most of the liquid.
Stir in the cooked chicken and pineapple chunks.
In a small bowl, mix cornstarch with 2 tablespoons of water to create a slurry. Stir into the skillet to thicken the sauce.
Drizzle with sesame oil and garnish with green onions before serving.
Notes
For extra flavor, marinate the chicken in soy sauce, garlic, and ginger for 30 minutes before cooking.
If using canned pineapple in syrup, reduce the brown sugar to 1 teaspoon or omit it.
Brown rice can be substituted but requires 40-45 minutes cooking time and extra half cup of liquid.
Use a 12-inch skillet or large 4-quart skillet with a tight-fitting lid to ensure rice cooks properly.