Brush chicken slices with a tablespoon of oil and toss in, McCormick Season All Lemon, Herb & Garlic Seasoning, coating evenly.
Heat remaining oil in a large frying pan over medium heat. Cook chicken for 4 – 5 minutes each side or until cooked through.
To serve, spread bun bases with mayonnaise and divide lettuce, onion and chicken fillets between bases, season with McCormick Sea Salt and Black Pepper and top with other half of bun.