Prepare all ingredients before cooking, as the recipe comes together quickly. Cut vegetables into small, even pieces so they cook at the same pace.

In a medium bowl, whisk together the sauce ingredients until smooth.

Place the chicken in a bowl. Add garlic powder and pepper, then stir to coat. Add the cornstarch and toss until the chicken is evenly covered.

Heat 2 tablespoons of olive oil in a deep skillet over medium-high heat.

Cook half of the chicken first for best browning. Shake off excess cornstarch and add the chicken to the hot pan. Cook for about 4 minutes, flip, and cook for another 3 to 4 minutes until browned and cooked through. Transfer to a plate.

Add the remaining tablespoon of olive oil and repeat with the second batch of chicken. Transfer to the plate once cooked.

If the skillet looks dry, add about a teaspoon of oil. Add the onions and cook for 1 minute, stirring occasionally.

Add the broccoli and bell pepper. Cook for about 3 minutes, stirring often, until the vegetables are tender-crisp. Cook slightly longer if you prefer softer vegetables.

Return the cooked chicken to the skillet. Quickly whisk the sauce again and pour it in. Cook, stirring constantly, until the sauce thickens and coats everything, about 1 minute.

Remove from heat and serve immediately, ideally with rice if desired.