Preheat the oven to 400°F (205°C). Spray a 9x13-inch baking dish with cooking spray and set aside.
Shred the cooked chicken into a medium mixing bowl (or dice into small pieces, if preferred).
Add the enchilada sauce and shredded cheese to the chicken and stir until evenly combined.
Lay one tortilla flat and place about 2 tablespoons of the chicken mixture near one edge. Tightly roll the tortilla around the filling and place seam-side down in the prepared baking dish. Repeat with remaining tortillas and filling.
Lightly spray the tops of the taquitos with cooking spray (or brush with melted butter) to promote browning.
Bake for about 15 minutes, or until the tortillas are golden brown. For extra crispiness, broil 1–2 minutes, watching closely to avoid burning.
Serve hot with optional hot sauce, sour cream, chives, and guacamole.
