In a small bowl, whisk together the minced garlic, grated ginger, Sambal Oelek, tamari, and toasted sesame oil to create the stir-fry sauce.
Cut the chicken breast into bite-sized 1-inch pieces.
Heat the avocado oil in a large skillet or wok over medium-high heat until shimmering.
Add the chicken to the skillet and cook for 5-6 minutes, stirring occasionally, until golden brown and cooked through.
Remove the chicken from the pan and set aside on a plate.
Add the broccoli florets and sliced red bell pepper to the same skillet, adding a splash of water if needed to steam-fry for 3-4 minutes until tender-crisp.
Return the chicken to the skillet and pour the prepared chili-garlic sauce over the mixture.
Toss everything together for 1-2 minutes until the sauce has thickened and evenly coated the chicken and vegetables.
Serve the stir-fry immediately over the warm cooked brown rice.
Garnish with sliced green onions and sesame seeds for a final touch of texture.