Begin by cutting the chicken breasts into bite-sized pieces to ensure they cook evenly on the grill. Chop your chosen vegetables, like bell peppers, zucchini, and red onion, into similarly-sized chunks.

In a mixing bowl, combine Dijon mustard, honey, and olive oil, whisking until well-blended and smooth.

Alternate threading pieces of chicken and vegetables onto skewers, spacing them evenly.

Coat the assembled skewers liberally with the marinade and let them marinate for 15-20 minutes at room temperature.

Preheat your grill to a high setting, around 400°F. If using wooden skewers, soak them in water for 30 minutes.

Place the marinated skewers directly on the grill and grill for about 10-12 minutes, turning frequently.

Remove the skewers from the grill and let them rest briefly before serving.