Add the soy sauce, brown sugar, garlic, ginger, sesame oil, rice vinegar, honey, and cornstarch directly to your crockpot. Whisk until well combined.
Add the chicken and sliced onion to the crockpot, turning the chicken to coat it in the sauce.
Cover and cook on LOW for 4 hours or until the chicken is tender and fully cooked.
Shred your chicken directly in the crockpot with two forks. If using butter, stir it in at this time until melted.
Add the broccoli florets to the crockpot during the last 20–30 minutes of cooking, or steam separately if you prefer a firmer texture.
While the broccoli cooks, prepare the ramen noodles or rice according to package directions. Drain well.
Serve the teriyaki chicken and broccoli over the cooked noodles or rice. Spoon extra sauce over top and garnish with sesame seeds and green onions if desired.
