In 12-inch ovenproof nonstick skillet, heat oil over medium heat. Cook potatoes, bell pepper and onion in oil 15 minutes, stirring occasionally, until very tender but not brown. Remove from heat.
In large bowl, beat eggs, salt and pepper with wire whisk until well blended. Stir in chorizo.
Set oven control to broil. Pour egg mixture into skillet, spreading evenly over potato mixture. Cook 5 minutes, without stirring, until bottom and edges are set.
Transfer skillet to oven; broil with top about 8 inches from heat 5 minutes or until top is just set. Place heatproof serving plate upside down over skillet; turn plate and skillet over. Remove skillet. Let stand 10 minutes before serving. Cut into 2-inch squares.