Heat oil in a large pot over medium heat. Add onion, garlic and ginger. Cook, stirring, until starting to soften, about 3 minutes.
Add chicken and cook, stirring, until opaque on all sides, about 4 minutes.
Stir in rice and broth and bring to a boil.
Reduce heat to maintain a simmer and cook, uncovered, stirring occasionally, until the rice is tender and the mixture has a porridge-like consistency.
Remove from heat and stir in fish sauce.
Garnish with scallions and/or eggs, if desired.
