Preheat the grill to medium-high heat.
Season the chicken breasts with salt and pepper on both sides.
Place the chicken on the grill and cook for 5-6 minutes on each side, or until fully cooked (internal temperature of 165°F). Remove from grill and let it rest for a few minutes.
While the chicken is resting, prepare the salad dressing. In a mixing bowl, whisk together the olive oil, balsamic vinegar, honey, Dijon mustard, salt, and pepper until well combined.
In a large platter or serving bowl, combine the mixed greens, cherry tomatoes, cucumber, bell pepper, and red onion.
Slice the grilled chicken into strips and arrange on top of the salad.
Drizzle the dressing over the salad and gently toss to combine before serving.
Feel free to customize the salad by adding your favorite ingredients such as avocados, nuts, or croutons.