In a large mixing bowl, combine the shredded chicken, softened cream cheese, green chilies, garlic powder, ground cumin, and Monterey Jack cheese. Season with salt and black pepper to taste. Mix everything together until well combined and creamy.
To make rolling the tortillas easier, warm them in a dry skillet over medium heat for about 30 seconds on each side, or microwave them for about 10-15 seconds until they are pliable.
Spread a thin layer of red enchilada sauce on the bottom of a 9x13 inch baking dish. Take a tortilla, add about 2-3 tablespoons of the chicken filling to the center, and roll it up tightly. Place the rolled tortilla seam-side down in the baking dish. Repeat this process with the remaining tortillas and filling.
Once all the enchiladas are in the baking dish, pour the remaining enchilada sauce over the top, ensuring they are well coated. Sprinkle the Mexican blend cheese evenly over the sauce.
Preheat your oven to 350°F (175°C). Cover the baking dish with aluminum foil and bake for 20 minutes. Remove the foil and bake for an additional 10-15 minutes, or until the cheese is melted and bubbly.
Once baked, remove the enchiladas from the oven and let them cool for a few minutes. Garnish with diced red onion, chopped cilantro, and finely chopped tomatoes before serving.