Chicken Club Brunch Ring

1/2 cup mayonnaise
1 tablespoon minced fresh parsley
2 teaspoons Dijon mustard
1-1/2 teaspoons finely chopped onion
1-3/4 cups cubed cooked chicken breast (1/2-inch cubes)
2 bacon strips, cooked and crumbled
1 cup (4 ounces) shredded Swiss cheese, divided
2 tubes (8 ounces each) refrigerated crescent rolls
2 plum tomatoes
2 cups shredded lettuce