How to Make It
Heat the oil in a large skillet over medium-high heat. Add the potatoes, onion, 1 of the poblanos, and ½ teaspoon salt. Cover and cook, stirring often, until the potatoes begin to soften, 12 to 14 minutes (reduce heat to medium if the skillet becomes too brown).
Add the broth, tomatoes, oregano, and the remaining poblano to the skillet and cook for 1 minute, scraping up the brown bits on the bottom of the pan. Season the fish with ¼ teaspoon each salt and black pepper and place on top of the vegetables. Cover and simmer until the potatoes are tender and the fish is opaque throughout, 8 to 12 minutes more. Sprinkle with additional oregano.