2. Place peppers on a foil-lined baking sheet; rub with 1 1/2 teaspoons oil. Broil 10 minutes or until blackened on all sides, turning occasionally. Wrap peppers in foil; let stand 10 minutes. Unwrap; remove skins and seeds. Coarsely chop peppers.
3. Heat remaining 1 1/2 tablespoons oil in a large skillet over high. Add onion, oregano, and garlic; sauté 3 minutes. Add tomato, adobo sauce, and 1/2 teaspoon salt; cook 4 minutes, stirring occasionally. Stir in peppers, juice, and chicken; cook 2 to 3 minutes or until slightly thickened.
4. Bring milk to a boil in a saucepan over medium-high. Reduce heat to medium-low; add remaining 1/4 teaspoon salt and polenta, whisking constantly. Cook 2 minutes or until thickened, stirring constantly. Place 3/4 cup polenta in each of 4 shallow bowls; top each serving with 3/4 cup chicken mixture.