Preheat your oven to 375°F (190°C). Butter or spray a 9x13-inch baking dish so the enchiladas won’t stick.

In a medium skillet over medium heat, melt the butter until it becomes foamy and releases a faint, nutty aroma. Add the diced onion and sauté until translucent, about 4 minutes.

Stir in the minced garlic, cumin, and chili powder and cook for 30 seconds until fragrant. Sprinkle the flour over the mixture and stir to form a roux; cook for 1–2 minutes until the flour loses its raw edge.

Gradually whisk in the chicken broth, scraping up any browned bits. The sauce will thicken and become glossy. Remove from heat and whisk in the sour cream until smooth. Season with salt and pepper, then fold in half of the shredded cheese.

In a bowl, combine the shredded chicken with a few tablespoons of the white sauce to moisten. Add chopped cilantro if you like herbal brightness.

Spoon about 2–3 tablespoons of the sauced chicken onto each warmed tortilla, roll tightly, and place seam-side down in the prepared baking dish.

Pour the remaining sauce evenly over the rolled tortillas, then sprinkle with the remaining cheese. Scatter a few fresh cilantro leaves on top for color before baking.

Bake until the sauce bubbles and the cheese is melted and golden in spots, about 20–25 minutes. Let rest for 5 minutes before serving; squeeze lime over the top for brightness.