Brush the olive oil over the chicken and then sprinkle with the teaspoon of salt and ½ teaspoon of pepper. Grill over high heat for 5-6 minutes on each side, cooking until the inner-most portion of the chicken reaches 165°F. Let the chicken rest for 10 minutes, then slice into bite-sized strips.
While the chicken cooks, add the white balsamic vinegar, apple juice, olive oil, honey, ½ teaspoon of salt, and ¼ teaspoon of black pepper to a bowl and whisk until smooth.
Assemble the salad by tossing the mixed greens with the romaine lettuce. Top with the onions, chicken, tomatoes, apples, pecans, and dressing.
