Prepare the chicken: Add the cornstarch to a bowl with a good amount of salt and pepper and mix. To another bowl, add the chopped chicken and pour the cornstarch mix on top. Use a wooden spoon to toss the chicken to coat it in the cornstarch.
Heat up a skillet for 2-3 minutes. Then add the oil and let it heat up for another minute or two. The oil and pan need to be very hot! Using tongs, carefully add the chicken to the pan, giving it enough space. You may need to cook the chicken in 2 batches. Cook on each side for 5 minutes - it should be golden and crispy. When cooked through, set the chicken aside.
Start the rice: Add 1 tsp oil to a pot over medium high heat. Add in the chopped veggies with a pinch of salt and cook, stirring frequently, on high heat for a minute. Add in the rice and water. Bring the pot to a boil, then reduce to a simmer and cover with a tight-fitting lid. Cook over low heat for 10 minutes, then turn off the heat to let the rice steam. No peeking or stirring!
Prepare the sauce: Add all the sauce ingredients to a measuring glass or bowl. Whisk well until all the ingredients are combined. Make sure to taste it!
Cook the sauce: Add the sauce to the same pan you used for the chicken over medium heat and bring the mixture to a boil. It takes about 3-5 minutes. Add the chicken back to the sauce, turn down the heat to medium/low and let the sauce cook uncovered until it's reduced by about half, stirring occasionally.
Assemble: Divide the cooked chicken and rice between three meal prep containers. Let the meals cool for at least 20 mins before covering them and storing them in the fridge!