Heat a grill or grill pan over medium heat. Rinse the chicken and pat dry with paper towels. Season the chicken with the black pepper and grill until cooked through, 5 minutes per side. Transfer to a cutting board and let rest 5 minutes; slice. Meanwhile, in a medium bowl, combine the greens, red peppers, artichokes, vinegar, oil, and basil. Top with the sliced chicken and serve with the toast.