Preheat oven to 350. Place bread on a baking sheet and bake until golden brown and very crisp, about 8 minutes. Lightly bruise 1 whole garlic clove and rub it over the surface of each piece of bread. Cut bread into 1-inch cubes and set aside.
Meanwhile, preheat a grill or grill pan over high heat. Season chicken breasts with Nu-Salt and pepper and spray lightly with Pam. Grill about 4 minutes per side, or until charred on the outside and just cooked through. Remove from grill and keep warm. Slice.
Meanwhile, together the 3 chopped garlic cloves with the fat-free sour cream, Dijon mustard, lemon juice and zest and pecorino. Season with freshly ground black pepper and Nu-Salt.
To serve, toss together the romaine with the sliced chicken, dressing and croutons. Adjust seasoning, if necessary. Although no actual salt is called for in this recipe, please add it as you see fit.