Heat 1 tablespoon of olive oil in a skillet over medium-high heat. Add the chicken pieces and cook until browned and cooked through, about 5-7 minutes.
Add the garlic, red and green bell peppers to the skillet. Cook for an additional 3-5 minutes until the peppers are tender.
In a bowl, mix together the brown sugar, soy sauce, sesame oil, ground ginger, Sriracha, and cornstarch. Pour the sauce over the chicken and vegetables, stirring until well combined. Cook for another 2-3 minutes until the sauce thickens.
Serve hot, garnished with toasted sesame seeds.
Notes
You can adjust the level of spiciness by adding more or less Sriracha. Feel free to substitute vegetables based on your preference.