To make a Thousand Island BBQ Dressing, in small bowl, stir together 1 cup mayonnaise, 1/4 cup chili sauce, 2 tablespoons smoky barbeque sauce, 1 tablespoon sweet pickle relish, and 1 teaspoon Worcestershire sauce until well blended.
In medium bowl, gently mix together beef, salt, Worcestershire sauce and pepper.
Shape into 4 (4 inch diameter) patties 3/4 inch thick. Heat grill to medium and place burgers on grill.
Top each burger with 1 slice cheese; grill 1 minute or until cheese has melted.
Place buns on grill; grill 30 to 60 seconds or until lightly toasted. Spread each bun with 2 Tbsp of the dressing.
Remove burgers from grill after cooking for 20 minutes. Top burgers with tomato, onion and lettuce.