Melt the butter in a 10-inch cast-iron skillet over medium-high heat. Add the poblano, scallions and jalapeno; cook, stirring occasionally, until slightly softened, 1 to 2 minutes. Add the corn and 3/4 teaspoon salt; cook, stirring occasionally, until the vegetables are soft, about 2 more minutes.
Whisk the eggs with 1/4 cup water and 1/2 teaspoon salt in a large bowl. Add the eggs to the skillet and cook, stirring constantly with a rubber spatula to form large curds, until the eggs are softly scrambled, about 2 minutes. Add the tortilla chips, 3/4 cup cheese and the cilantro to the skillet; cook, stirring, until well combined, 1 to 2 more minutes.
Sprinkle the scramble with the remaining 1/4 cup cheese and top with avocado, sour cream, pico de gallo and more cilantro.