In a grill pan or skillet over medium heat, cook the chicken breasts for about 6-7 minutes on each side until fully cooked. Once done, let them rest for a few minutes before cutting into small, bite-sized pieces.
In a small bowl, whisk together honey, Dijon mustard, olive oil, salt, and pepper until well combined to create the dressing.
In a large mixing bowl, combine the cooked chicken, mixed salad greens, cherry tomatoes, cucumber, and red onion. Toss gently to mix the veggies and chicken.
Drizzle the honey mustard dressing over the salad and toss again until everything is evenly coated in the dressing.
Serve the salad on individual plates and sprinkle with chopped walnuts or almonds if desired for an added crunch.
Feel free to customize the salad by adding other ingredients such as avocado, bell peppers, or carrots.
This salad can be prepped ahead of time; just store the dressed salad in the refrigerator for up to 2 days, but keep the nuts separate until just before serving to maintain their crunch.