Preheat the oven to 450°F and lightly grease a 9x13-inch baking dish with some of the melted butter.
Heat the olive oil in a skillet over medium-high heat.
Season the chopped chicken with the taco seasoning, add it to the hot skillet, and cook about 5 minutes until the chicken is cooked through.
Stir in the frozen corn, refried beans, salsa, and shredded cheddar; cook 2 minutes more until the corn is no longer frozen and the mixture is heated through.
Remove from heat, stir in the chopped cilantro, and mix to combine.
Lay a 6-inch tortilla flat, place about 2 tablespoons of the chicken mixture near the edge, then tightly roll the tortilla and place seam-side down in the prepared baking dish. Repeat with remaining tortillas and filling.
Brush the tops of the rolled taquitos with the melted butter to help them crisp while baking.
Bake for about 15 minutes, or until the taquitos are crisp and golden brown.
Serve warm with extra salsa on the side.