In a small mixing bowl, whisk together the gochujang paste, tamari, honey, and minced ginger until smooth to create the spicy stir-fry sauce.
Slice the chicken breast into bite-sized cubes and mince the garlic clove.
Heat the toasted sesame oil in a large skillet or wok over medium-high heat until shimmering.
Add the chicken cubes to the skillet and sauté for 5 to 7 minutes until they are golden brown and cooked through.
Add the broccoli florets and sliced red bell pepper to the pan, stir-frying for an additional 3 to 4 minutes until the vegetables are tender-crisp.
Stir in the minced garlic and cook for 30 seconds until fragrant, being careful not to burn it.
Pour the gochujang sauce over the chicken and vegetables, tossing constantly for 1 minute until the sauce thickens and coats everything in a glossy glaze.
Remove from heat and garnish with thinly sliced green onions and sesame seeds before serving.