Heat the butter in a large skillet over medium heat.
Add the onion, jalapeños, and garlic and cook until softened, about 3 minutes.
Add the pickled Serrano peppers (if using) and tomatoes, and cook just until tomatoes begin to break down, about 3 more minutes.
In a medium bowl, add the corn starch to the evaporated milk, and whisk until dissolved and incorporated. Whisk in the water and add to the veggies in the skillet.
Stir with a wooden spoon until just starting to thicken.
Add in the cheese and stir until completely melted.
Stir in the cumin, onion powder, pepper, salt, green chilies, and cilantro. Bring to just a simmer and let cook for a couple of minutes.
Transfer to a warmed bowl, or small slow-cooker, and top with Fresh Pico de Gallo and warmed tortilla chips.
