01 - In a mixing bowl, whisk together teriyaki sauce, soy sauce, pineapple juice, olive oil, garlic powder, and black pepper until well combined. Add chicken breasts, turning to coat evenly. Cover and refrigerate for at least 30 minutes or up to 2 hours for deeper flavor penetration.
02 - Preheat grill to medium-high heat (approximately 375°F to 400°F). Lightly oil the grates to prevent sticking.
03 - Remove chicken from marinade, allowing excess to drip off. Place chicken breasts on the grill and cook for 6 to 7 minutes per side until internal temperature reaches 165°F and distinct grill marks form. During the final 2 minutes, top each breast with a slice of cheese and close the lid to allow melting.
04 - Place pineapple rings directly on the grill grates. Cook for 1 to 2 minutes per side until lightly charred with visible caramelization. Remove and set aside.
05 - Spread butter evenly on the cut sides of each bun. Place buttered side down on the grill and toast until golden brown, approximately 30 to 60 seconds. Remove from heat.
06 - Spread mayonnaise evenly across the bottom half of each toasted bun. Add Sriracha or hot sauce if desired for a spicy kick.
07 - Layer each bottom bun with a lettuce leaf, followed by the grilled chicken breast with melted cheese, a charred pineapple ring, a tomato slice, and a generous portion of sliced red onion. Cap with the top bun and press gently to secure.
08 - Serve immediately while warm alongside your preferred side dishes.