Heat a large skillet over medium heat and spray with cooking spray or add a small drizzle of olive oil. Add chicken and cook for 5–6 minutes per side, or until cooked through and the internal temperature reaches 165°F.
Add romaine, apple, cucumber, feta, and pecans to a large bowl. Top with cooked chicken. Drizzle with honey mustard dressing and toss to combine, or serve the dressing on the side. Divide into bowls and enjoy!