Preheat the oven to 425°F. Line a 9x13-inch (or larger) baking sheet with parchment paper.
Heat 2 tablespoons of olive oil in a large skillet over medium-high heat.
Add onion and cook until softened, about 3 minutes.
Stir in chicken, salsa, taco seasoning, salt, and pepper.
Cook for 2 to 3 minutes, then remove from heat and stir in lime juice.
Wrap tortillas in a damp paper towel, then warm tortillas in the microwave for 30 seconds to make them pliable.
Spoon the chicken mixture onto one half of each tortilla.
Sprinkle with cheese, fold over, and arrange them on the prepared baking sheet. (Use two baking sheets if needed.)
Lightly brush the tops of the tortillas with the remaining olive oil.
Bake for 12 to 15 minutes, or until tacos are golden brown and crispy.
Serve warm with your favorite toppings such as sour cream, cilantro, shredded lettuce, or extra salsa.