In a small bowl mix the Teriyaki sauce ingredients.
In a large heavy bottom sauté pan, over medium to high heat, add the olive oil. Add the chicken and carrots and cook stirring occasionally until almost tender, about 6-8 minutes. Add the garlic and cook further for another minute.
While the chicken is cooking, place the broccoli on a safe microwave dish and microwave for 6-8 minutes
Add the Teriyaki sauce from the bowl to the chicken and carrots and stir for about 1-2 minutes or until it thickens. Turn heat off and add the broccoli and pepper flakes if using. Stir to combine.