In medium bowl, mix together tomato sauce, vinegar, garlic, chili powder, cumin, oregano, and sugar. Season with Adobo; set aside.
Heat oil in large skillet over medium-high heat. Season chicken with Adobo. Cook chicken, turning once, until light golden brown on both sides, about 5 minutes. Add reserved tomato sauce mixture to pan; bring to a boil (be careful, the tomato sauce can splatter). Lower heat to medium low. Simmer, covered, flipping once, until chicken is cooked through (thermometer will register 165°F when inserted into thickest part of breast), about 20 minutes.
Transfer chicken to cutting board; reserve sauce in pan. Remove and discard bones and skin. Using two forks, shred chicken breast. Transfer chicken to skillet with sauce, mixing to combine; continue to cook until sauce reduces and blends into chicken, and mixture begins to caramelize, about 10 minutes more.
To serve, spoon shredded chicken onto tortillas. Garnish with desired toppings.