Creating the Teriyaki Chicken Casserole is straightforward if you follow these simple steps:

1. Preheat Your Oven: Begin by preheating your oven to 350°F (175°C) to prepare for baking.
2. Cook the Chicken: Heat olive oil in a large skillet over medium heat. Add the cubed chicken and cook until it’s no longer pink, about 5-7 minutes.
3. Add Vegetables: Once the chicken is cooked, add the broccoli, bell peppers, carrots, and snap peas. Sauté for an additional 5 minutes to soften the vegetables slightly.
4. Mix in Teriyaki Sauce: Pour in the teriyaki sauce and stir until everything is well-coated. Let it simmer for another 2-3 minutes.
5. Combine with Rice: In a large mixing bowl, combine the cooked rice with the chicken and vegetable mixture, ensuring even distribution.
6. Prepare for Baking: Transfer the mixture into a greased 9×13 inch casserole dish, spreading it out evenly.
7. Top with Cheese: Sprinkle the shredded mozzarella cheese evenly over the top of the casserole.
8. Bake: Place the casserole in the preheated oven and bake for 30-35 minutes, or until the cheese is melted and bubbly.
9. Garnish: Remove from the oven and let it cool slightly. Optionally, sprinkle sesame seeds and sliced green onions on top for added flavor and presentation.
10. Serve: Spoon the casserole onto plates and enjoy!

These steps will guide you in creating an incredible dish that is destined to become a family favorite.