Brush chicken breasts with olive oil and season with salt, black pepper, and garlic powder. Preheat a grill or grill pan to medium-high heat.
Grill the chicken for about 5-7 minutes per side until cooked through (internal temperature of 165°F). In the last minute of grilling, place a slice of cheese on each piece to melt.
Lightly toast the buns on the grill or in a pan for a golden-brown crunch. For another great sandwich option, try these Sausage Cream Cheese Crescents.
Spread honey mustard or mayonnaise on the buns. Layer with lettuce, tomato, grilled chicken, crispy bacon, and the top bun.