Heat a large pot over medium-high heat. Add the chicken cubes and sprinkle with garlic powder, ground ginger, and black pepper. Cook for about 10 minutes or until the chicken is cooked through.
Add the olive oil to the pot and stir in the onions, garlic, and ginger. Cook for about 5 minutes or until the vegetables are softened.
Stir in the mushrooms and cook for an additional 3 minutes.
Pour in the chicken broth and bring to a boil. Reduce heat to low and add the fish sauce, brown sugar, and cinnamon sticks. Simmer for 30 minutes.