Add the sauce ingredients to a small bowl. If you don't have quite enough pineapple juice to make ¾ cup, just top the rest up with water. Whisk until smooth.

Prep your veggies.

Cut the chicken into 1" pieces and add them to a bowl. Toss them with the garlic powder and some pepper. Add the cornstarch and toss until coated.

Add 2 tablespoons of olive oil to a deep skillet over medium-high heat. Let the pan heat up for a few minutes. Cook the chicken in two batches (don't crowd the pan). Cook the chicken for 4 minutes and then flip and cook for another 3-4 minutes or until browned and cooked through (165F). Transfer each batch of chicken to a plate when it's done.

If the pan is dry, add a small splash of olive oil (a teaspoon or so), and then add the pineapple. Let it cook without stirring it for about a minute.

Stir in the peppers and onions and cook for another 3 minutes, stirring occasionally. Veggies will be tender-crisp.

Add the chicken back to the pan and then stir in the sauce. Let it bubble until thickened (about 1-2 minutes), then take the pan off the heat and serve immediately over rice or noodles.