Adjust a V-shaped roasting rack so each side is at a 45° angle to the base. Cut 2 sheets of foil, each 12 inches long. Fold each sheet lengthwise to make a strip that is about 3 inches wide. Drape 1 strip from center of the V over and down to the base of the rack. Fold foil at each end to secure to rack. Repeat to secure second piece of foil to other side of the rack. Drape each flour tortilla with its center over the highest point on one side of the rack (foil keeps tortilla from curling inward as it bakes).
Bake tortillas in a 450° oven until lightly browned, about 5 minutes, then lift off racks and set aside (they continue to crisp as they cool). If making more than 1 hour or up to a day ahead, package airtight.
As tortillas bake, rinse chicken and pat dry. Melt 1 tablespoon jelly (in a microwave oven or in a small pan over medium heat, stirring occasionally). Brush all the melted jelly onto the smooth sides of breast halves. Put corn chips on a small plate and press jelly-coated side of chicken into chips so they stick. Set breasts, chips up, in an 8- or 9-inch square pan. Pat any remaining chips onto chicken.
Bake in a 450° oven until chicken is no longer pink in thickest part (cut to test), 15 to 20 minutes.
Meanwhile, in a bowl, mix beans, salsa, and remaining jalapeño jelly.
Lift breasts from pan with a wide spatula. If desired, cut each piece crosswise into 4 or 5 equal slices.
Set each tortilla shell on a plate. Put half the lettuce into each shell. Top lettuce equally with the bean mixture. Use the spatula to transfer a breast onto beans in each tortilla shell. Garnish with avocado and add sour cream and salt to taste.