Cut the chicken into 1-inch cubes.
In a bowl, combine 1 Tbsp arrowroot (or cornstarch), garlic powder, onion powder, 1/4 tsp salt, and 1/4 tsp black pepper; toss the chicken to coat evenly.
Heat 1 Tbsp olive oil in a large skillet over medium-high heat. Add the chicken in an even layer and cook, stirring as needed, until lightly browned and cooked through, about 4–5 minutes; transfer to a plate.
Add the remaining 1 Tbsp olive oil to the hot skillet. Add the trimmed green beans, season with a little salt and pepper, and sauté until they develop slight char and are tender-crisp, about 6 minutes.
Whisk together chicken broth, soy sauce, honey, minced garlic, and grated ginger in a small bowl.
Mix 2 tsp arrowroot (or cornstarch) with 2 tsp water until smooth to make a slurry and set aside.
Return the cooked chicken to the skillet with the green beans. Pour the sauce over everything, then add the slurry and stir to combine.
Bring the sauce to a boil, then reduce heat and simmer until the sauce thickens and coats the chicken and green beans, about 1–2 minutes.
Remove from heat and top with chopped green onions and optional sesame seeds. Serve immediately.