**Preheat the Oven:** Preheat your oven to 375°F (190°C).
**Mix the Base:** In a large mixing bowl, combine the shredded chicken, cream cheese, sour cream, and enchilada sauce. Stir until well blended.
**Add Cheeses and Extras:** Fold in the Mexican blend cheese, cheddar cheese, green chilies, and diced red onion.
**Assemble the Dip:** Transfer the mixture to an oven-safe baking dish. Spread it out evenly, and sprinkle extra Mexican blend cheese on top.
**Bake:** Bake in the preheated oven for 20-25 minutes, or until the dip is bubbly and the cheese on top is melted and golden.
**Garnish and Serve:** Remove from the oven, sprinkle with chopped cilantro if desired, and serve hot with tortilla chips, crackers, or fresh veggies.