Preheat your oven to 375°F (190°C).
In a large skillet, heat the olive oil over medium heat. Add the diced onion and cook until softened, about 3-4 minutes.
Add the minced garlic, ground turkey, cumin, chili powder, salt, and black pepper to the skillet. Cook until the turkey is browned and cooked through, about 6-8 minutes.
Stir in the black beans, corn, and 1/2 cup of salsa. Cook for an additional 2-3 minutes until heated through.
Spread 1/2 cup of salsa evenly on the bottom of a 9x13-inch baking dish.
To assemble the enchiladas, place about 1/4 cup of the turkey mixture in the center of each tortilla. Sprinkle with a little cheese, then roll up the tortilla and place it seam-side down in the baking dish. Repeat with the remaining tortillas.
Once all enchiladas are in the dish, pour the remaining salsa over the top and sprinkle with the remaining cheese.
Cover the dish with aluminum foil and bake for 20 minutes. Remove the foil and bake for an additional 10 minutes, or until the cheese is bubbly and golden.
Let the enchiladas cool for a few minutes before serving. Top with sour cream and chopped cilantro.