1. Heat a large nonstick skillet over medium-high heat. Coat pan with cooking spray. Add 1/2 cup onions; coat onions with cooking spray. Cook 1 minute, stirring occasionally. Add shrimp and chili powder; cook 4 minutes or until desired degree of doneness, stirring occasionally. Remove from heat. Add lime juice, butter, and salt, and stir until butter melts. Sprinkle with 1/4 cup onions.