In a small pot bring the orange zest, orange juice, beef stock, brown sugar, vinegar, soy sauce, Sriracha, ginger, garlic, and marmalade to a low boil, stirring often, until the sauce thickens, about 15 minutes.
In a large skillet heat 1 tablespoon olive oil over medium heat.
Sprinkle the chicken with salt, pepper, and garlic powder.
Saute the chicken in the pan for 4-5 minutes. Remove to a bowl.
Add another tablespoon of olive oil to the skillet and stir fry the broccoli for 5 minutes.
Return the chicken to the skillet and pour the sauce over top of the chicken and broccoli.