Preheat the oven to 375°F (190°C).
Heat the vegetable oil in a large skillet over medium heat. Add the chopped onion and cook until softened, about 5 minutes.
Add the minced garlic and cook for 1 minute until fragrant.
Stir in the shredded chicken, ground cumin, chili powder, smoked paprika, cayenne pepper, salt, and black pepper. Cook for 3-4 minutes until the spices are well combined and heated through. Remove from heat.
Pour 1 cup of enchilada sauce into the bottom of a 9×13 inch baking dish and spread evenly.
Warm the corn tortillas in a microwave or on a skillet to make them pliable.
Dip each tortilla briefly into the remaining 1 cup of enchilada sauce, then spoon about 1/4 cup of the chicken mixture down the center of the tortilla.
Sprinkle about 2 tablespoons of shredded cheese over the chicken filling, then roll up the tortilla tightly and place seam-side down in the baking dish.
Repeat with the remaining tortillas and filling, arranging them side by side in the dish.
Pour any remaining enchilada sauce over the top of the rolled tortillas.
Sprinkle the remaining shredded cheese evenly over the enchiladas.
Bake uncovered in the preheated oven for 20 minutes, or until the cheese is melted and bubbly.
Remove from oven and let cool for 5 minutes.
Garnish with chopped fresh cilantro and sliced jalapeño if desired.
Serve warm with sour cream on the side.