Melt the butter in a 12-inch heavy-bottomed nonstick or cast-iron skillet over medium-high heat until the foaming -subsides. Add the potatoes and cook, stirring frequently with a rubber spatula or wooden spoon, until they are tender and light golden brown, about 12 minutes total. Add the cooked corned beef, onion, and poblano, and cook, stirring frequently, until the vegetables are beginning to soften, about 4 minutes. Add the ketchup or chili sauce and hot sauce, stir to combine, and season to taste with salt and pepper.
