In a bowl, combine soy sauce and brown sugar. Add the chicken thighs and marinate for at least 30 minutes, or up to 2 hours in the refrigerator for more flavor.
Heat vegetable oil in a large skillet over medium-high heat. Remove chicken from the marinade (reserve the marinade) and add to the skillet. Cook for about 5-7 minutes on each side until golden brown and cooked through. Remove chicken from the skillet and set aside.
In the same skillet, add minced garlic and ginger. Sauté for about 1 minute until fragrant.
Pour in the reserved marinade and chicken broth. Bring to a simmer, then reduce heat to low. Return the chicken to the skillet and let it simmer in the broth for an additional 10 minutes.
Stir in sesame oil and black pepper. Taste and adjust seasoning if necessary.
Serve the chicken over cooked white rice, spooning the garlic ginger broth over the top. Garnish with sliced green onions and sesame seeds.