Heat 1 tbsp of olive oil in a skillet over medium-high heat.
Add the broccoli, sliced mushrooms and yellow bell pepper to the heated skillet, and cook for 5-6 minutes until the vegetables begin to become tender. Remove the vegetables, cover them and set aside for later.
Place one teaspoon of olive oil in the heated skillet, and add the chicken breast pieces. Cook until the chicken is no longer pink in the center and cooked through. Add salt and pepper to taste. Mix the vegetables back into the skillet.
In a separate bowl, combine the soy sauce, sugar, chicken broth, sesame oil and cornstarch, and mix well.
Pour the sauce over the chicken and vegetables in the skillet, and stir to coat. Cook for 2-3 minutes until everything is coated well and the sauce has thickened.
