Salt and pepper chicken breast on both sides.
In a skillet, over medium-high heat, heat 1-½ tbsp. vegetable oil.
Add chicken breast and cook until done (when internal temperature reaches 165°F).
Remove chicken from skillet and thinly slice.
Place a tortilla on a hot skillet.
On one side of the tortilla, place ¼ cup of shredded cheese and ½ slice American cheese.
Place half of the chicken on top of the cheese.
On the other side, spread about 1-½ tbsp. sauce.
Place the second tortilla on top of the chicken and cheese.
Fold tortilla over and press gently with a spatula.
Cook until cheese is melted and bubbly; 2 – 4 minutes on each side.
Remove from heat and use a pizza cutter to slice each quesadilla into 4 pieces.