Heat a large skillet over medium heat and melt 1/2 tablespoon of butter.
Place one tortilla flat in the skillet.
Spread a quarter of the shredded chicken evenly over the tortilla.
Sprinkle 1/2 cup of the Mexican cheese blend over the chicken.
Add 2 slices of crumbled bacon evenly on top.
Drizzle 2 tablespoons of ranch dressing over the ingredients.
Add a quarter cup of diced tomatoes and a tablespoon of chopped red onion.
Sprinkle with 1/2 tablespoon of fresh cilantro.
Top with another tortilla.
Cook for 3-4 minutes until the bottom tortilla is golden brown and cheese starts melting.
Carefully flip the quesadilla and cook another 3-4 minutes until golden brown and cheese is fully melted.
Remove from skillet and let cool for a minute.
Cut into four wedges and serve warm.
Repeat process for remaining tortillas and ingredients.