In large pan over medium-high heat, heat 1 TBSP oil. Add broccoli and cauliflower to the pan. Cook 4 to 5 minutes, stirring occasionally, until tender-crisp. Transfer to plate and set aside.
To the pan, add remaining oil and heat until shimmering. Add chicken and cook, stirring occasionally, until chicken is browned on all sides and at least 165°F on instant read thermometer 4 to 5 minutes. Add garlic and cook 1 minutes until fragrant.
In a small bowl whisk together orange juice, soy sauce, honey and cornstarch, Pour over chicken and vegetables. Stir continuously until sauce starts to thicken. Remove from heat and serve.