Prep the ingredients before you start cooking - once the recipe is started, it goes quickly. Cut the veggies into bite-size pieces (make sure that the broccoli is cut quite small) so they cook at a similar rate.

Add the sauce ingredients to a medium bowl and whisk everything together.

Cut the chicken into 1" pieces and add them to a bowl. Sprinkle the pieces with the garlic powder and some pepper. Stir to combine. Add the cornstarch and stir until the chicken is coated.

In a deep skillet, over medium-high heat, add 2 tablespoons of the oil. Let the pan heat up for a few minutes.

You will cook the chicken in two batches to get the best browning. Add half the chicken to the skillet, shaking off the excess cornstarch prior to adding it to the pan. Cook for 4 minutes and then flip and cook for another 3–4 minutes or so. I flip using tongs to make it easy. The chicken should be browned and cooked through. Transfer to a plate. Repeat for the second batch, adding the third tablespoon of olive oil to the skillet.

If the pan is dry, add a small splash of olive oil (a teaspoon or so), and then add the onions. Cook for 1 minute, stirring a few times.

Add in the broccoli and peppers, and cook for 3 minutes, stirring often. Veggies should be tender-crisp. Give it a little longer if you want them softer.

Add the chicken back to the pan and stir in the sauce (whisk it again quickly prior to pouring it in). Let it bubble until thickened (less than a minute), stirring constantly so everything is coated. Take the pan off the heat and serve immediately.