In a skillet, heat the olive oil over medium heat.

Add the shredded chicken and cook until warmed through.

In a mixing bowl, combine the cherry tomatoes, cucumber, and spinach.

In a small bowl, whisk together the olive oil, balsamic vinegar, mustard, salt, and pepper.

Pour the dressing over the salad and toss to combine.

Top the salad with the warm chicken and serve immediately.