Mix red wine vinegar, water, sugar and salt together until dissolved. Add onions and stir until coated. Cover and set aside.
In a medium saucepan add chicken breasts, salt and pepper. Cover the chicken with water and bring to a boil. Cook chicken about 15 to 20 minutes, or until fully cooked. Set aside to cool.
Take your chicken and shred with two forks or your hands. Add the barbecue sauce and mix until well-combined.
Preheat oven to 400°F. On a large sheet tray, spread bag of chips evenly. Top with shredded chicken, cheese, jalapeños and corn. Bake for 12 minutes, or until the cheese is melted.
Top your nachos with pickled onions and dollops of sour cream. Serve immediately.