Season each side of the chicken breast with the cajun seasoning mix.
Heat a large saute pan under medium high heat and add about a tablespoon of olive oil. Add chicken breast and cook for about 4-5 minutes, or until browned. Flip over and cook an additional 4-5 minutes, or until cooked thoroughly. Set chicken aside on cutting board to rest.
Make vinaigrette by combining olive oil, apple cider vinegar, maple syrup, Dijon mustard, spicy brown mustard, shallot, and garlic in a small bowl. Whisk until mixture is emulsified (no separation of acid and oil). Season with salt and pepper, to taste.
In a large bowl, toss the greens with about 2 tablespoons of the vinaigrette and divide among two plates. Top greens with trail mix and sliced apples. Then top with sliced chicken breasts. Serve with additional dressing, if desired.