Heat skillet to medium heat.
Sprinkle chili powder, salt, cumin, and garlic powder onto chicken and stir to combine well.
Add olive oil to hot skillet and add chicken.
Cook while frequently stirring until chicken is no longer pink. (About 5-6 minutes)
Remove cooked chicken from pan and set aside on a plate.
Add sliced onions and peppers to the same pan and cook until crisp-tender.
Add chicken back into pan, including any pan juices that may have accumulated on the plate, and heat through.
Serve on tortillas or low carb style on a big salad.