Heat grill to medium heat.
Mix ground beef and chorizo just until blended; shape into 4 (1/2-inch-thick) patties.
Grill 4 to 5 min. on each side or until done (160°F); top with Singles. Add buns, cut-sides down, to grill. Cook 1 min. or until Singles are melted and buns are lightly toasted.
Place lettuce on bottom halves of buns; top with chips, guacamole, sour cream, cheeseburgers and tomatoes. Cover with tops of buns.