Combine first 3 ingredients. Sprinkle steak with chili powder mixture. Place on a broiler pan coated with cooking spray. Broil 4 minutes on each side or until desired degree of doneness. Let stand 5 minutes before slicing.
Heat a large nonstick skillet coated with cooking spray over medium-high heat. Add onion; sauté 4 minutes. Add tomatoes, chile, and sugar; bring to a boil. Reduce heat, and simmer, uncovered, 4 minutes. Thinly slice steak across grain. Serve steak with tomato mixture and warm tortillas.
Note: Use your remaining chipotle chiles in adobo sauce in Chipotle Mashed Potatoes or Chipotle Black Bean Chili.