Dice the onion and bell pepper. Whisk chicken stock and cornstarch into a bowl.
Season the chicken breast with some kosher salt and ground pepper on both sides. Heat oil in a skillet over medium-high heat.
Add chicken to the hot oil and sear each side until nicely golden brown and cooked through, about 5 to 8 minutes per side, depending on its thickness. Transfer the cooked chicken to a plate and allow it to sit for a few minutes, then slice it.
To the same skillet, add onion, bell pepper, garlic, and red chili; cook for a few minutes until veggies are softened.
Pour in the stock-cornstarch mixture and the coconut milk. Whisk well to combine; the sauce will start to thicken quite fast. Stir in the lime juice & zest.
Allow it to simmer for about 5 minutes. Return the sliced chicken to the pan, and spoon over the hot sauce.
Garnish with fresh cilantro leaves and serve warm.
Notes
Serving: 6 if using 6 chicken breast. Serice size is 1 chicken breast.
You may switch out the chicken with shrimp. If you would like to use boneless chicken thighs you may but it's higher in fat and not as lean as chicken breast.
Coconut milk: This is used as a healthier option in place of heavy or whipping creamy. You may use 2% milk but the consistency of the sauce won't be as thick.
Chicken stock can be replaced with water or vegetable stock
Any flour can be used in place of cornstarch but again the consistency of the sauce will vary slightly.
Use fresh garlic cloves for a more robust flavor, but they can be replaced with 1 tablespoon of garlic powder.