(Optional) In a pot over medium heat, brown chicken on both sides in a couple of tablespoons of olive oil. Remove it to a plate. This isn't necessary but can be tasty, especially if you have skin-on chicken.
Over medium heat, sautee minced garlic in olive oil for a few seconds. Add soy sauce and brown sugar. Whisk to combine.
Whisk in chicken broth (I recommend Better Than Bouillon, prepared according to package directions).
In a separate dish, whisk together 1 tablespoon or cornstarch with 2 tablespoons of cold water until smooth. Slowly add to garlic chicken broth mixture in pot, whisking well to combine. Allow sauce to thicken for a few minutes.
Add chicken (pre-browned if desired, as described above) and turn to coat in the sauce.
Either cover with pot lid and cook over low heat until chicken is done, or cover and bake in 350 degree F oven until chicken is done. Cooking time will depend on thickness of chicken. My chicken was boneless and I browned it first - It took less than ten minutes for it to be done. An instant read thermometer* inserted in the chicken should read 165 degrees F.
If you are using skin-on chicken you can broil it for a few seconds to crisp it up.
Garnish with green onions and enjoy!