Begin by heating the olive oil in a large skillet over medium heat. Once hot, add the bite-sized chicken thighs, seasoning them with salt and pepper. Sauté until the chicken is browned and cooked through, about 5-7 minutes.
Stir in the taco seasoning, flour, and minced garlic. Cook for an additional minute to toast the spices. Gradually pour in the chicken stock, stirring to combine. Allow the mixture to simmer for a few minutes until it thickens slightly. Remove from heat and set aside.
Lay out four tortillas on a clean surface. Evenly distribute the chicken mixture onto each tortilla. Sprinkle each with shredded cheddar cheese, chopped scallions, green chiles, and a drizzle of green enchilada sauce. Top with the remaining tortillas.
In the same skillet, heat vegetable oil over medium heat. Carefully place one quesadilla in the skillet, cooking for about 3-4 minutes on each side or until golden brown and the cheese melts. Repeat with the remaining quesadillas, adding more oil as needed.
Once cooked, remove the quesadillas from the skillet and let them cool slightly. Slice into wedges and serve with restaurant-style salsa and sour cream for dipping.