- Cut each chicken breast lengthwise in 3 strips; cut crosswise into thin pieces (diced is also good). 
- If using the Homemade Fajita Seasoning add 2 tablespoons of oil in a small bowl and combine well. OR: Combine the chili powder, cumin, oregano, garlic powder with 2 tbsp of the oil in a small bowl. 
- Toss the seasoning mix with the chicken, coating very well. Leave the chicken to marinate this way while you are chopping the vegetables or refrigerate and let it marinate for a couple of hours. 
- Heat the 1 tablespoon of oil in a large skillet over medium high heat. 
- Add the chicken and cook 7 to 8 minutes or until no longer pink in the center, stirring frequently. Let the chicken brown up nicely before turning it. 
- Stir in the bell peppers and onion. Cook the vegetables for 5 to 7 minutes or until the vegetables are tender.