In a large skillet, heat 1 tablespoon of olive oil over medium heat. Add chopped onions and sauté for about 3-4 minutes until they become translucent. Then, mix in the shredded chicken, cumin, chili powder, salt, and pepper, stirring everything together for an additional 2-3 minutes until heated through and fragrant.

While the chicken mixture is cooling, preheat your oven to 375°F (190°C). Grease a 9x13-inch baking dish with a bit of olive oil or cooking spray.

Take each tortilla and lay it flat on a clean surface. Spoon a generous amount of the chicken mixture into the center of each tortilla, sprinkle with a bit of cheddar and Monterey Jack cheese, then roll the tortilla tightly around the filling. Place each rolled enchilada seam-side down in the greased baking dish.

In a medium saucepan over medium heat, whisk together 1 cup of sour cream, 1 cup of heavy cream, and 1 cup of chicken broth. Stir continuously for 5-7 minutes until the mixture thickens and is creamy. Add garlic powder, smoked paprika, cayenne pepper, and salt to taste.

Once your creamy sauce is ready, pour it generously over the prepared enchiladas in the baking dish, making sure each enchilada is well-coated. Then, sprinkle any remaining cheese evenly on top. Bake in the preheated oven for 20-25 minutes, or until the sauce is bubbly and golden brown around the edges.

After removing the cheesy chicken enchiladas from the oven, let them rest for about 5 minutes to allow the flavors to settle. Garnish with fresh salsa and chopped cilantro before serving.