Line your crock pot with a cooking liner (optional but recommended)
Place chicken in crock pot. Pour 1 C BBQ sauce over chicken and season with garlic salt.
Cook on low 4 hours.
Remove chicken from crock pot and shred, using 2 forks. Pour remaining ¼ C BBQ sauce to shredded chicken and stir together.
Preheat oven to 450.
Spray 1 side of 3 tortillas with cooking spray, olive oil or brush with melted butter. Place shredded chicken mixture on each. Sprinkle bacon, scallions and cheese over the chicken. Place remaining tortillas on top and spray the top side with cooking spray.
Place each quesadilla on a rack placed over a baking sheet (the rack will allow air to circulate under the quesadilla preventing the bottom from getting soggy) and cook 10 minutes or until nicely brown and crispy.
Slice and serve.