Prep the chicken: Pat chicken breasts dry and trim any excess fat.
Cut into 1-inch pieces for faster cooking and better sauce coverage. Season with salt, pepper, smoked paprika, and onion powder.
Make the honey mustard sauce: In a bowl, whisk Dijon mustard, yellow mustard, honey, vinegar or lemon juice, garlic, a pinch of salt and pepper, and a splash of chicken broth if you want a thinner sauce. Taste and adjust sweet/tangy balance.
Prep the broccoli: Cut into florets.
Rinse and shake dry. For extra tenderness, microwave in a covered bowl for 1 to 2 minutes or blanch briefly. This step helps keep broccoli bright green and quick-cooking.
Sear the chicken: Heat a large skillet over medium-high with 1 tablespoon oil.
Add chicken in a single layer. Cook 5 to 7 minutes, stirring once or twice, until cooked through and lightly browned. Remove to a plate.
Cook the broccoli: In the same skillet, add a small splash of oil if needed.
Add broccoli with a pinch of salt. Stir-fry 3 to 4 minutes until crisp-tender. Add a tablespoon of broth if the pan gets dry.
Sauce it up: Return chicken to the pan.
Pour in the honey mustard sauce, tossing to coat. Simmer 1 to 2 minutes until the sauce slightly thickens and clings to the chicken and broccoli. Add red pepper flakes if you like heat.
Finish and garnish: Turn off heat.
Squeeze a little lemon over the top and sprinkle with chopped parsley. Taste and adjust salt, pepper, or honey.
Portion for meal prep: Divide evenly into 4 containers. For lower calories, serve as is.
If you want more volume, add cauliflower rice, steamed green beans, or a small scoop of cooked quinoa on the side.