Slice the onion into thin strips and cut the bell peppers into slices.
In a bowl, mix 1 tablespoon olive oil, juice of half a lime, chili powder, smoked paprika, onion powder, black pepper, cumin, and ½ teaspoon salt.
Cut the chicken into strips and toss well in the marinade.
Heat 1 tablespoon olive oil in a skillet over medium-high heat.
Cook half of the chicken for 3–5 minutes until fully cooked. Remove and repeat with remaining chicken.
Set chicken aside and add remaining oil to the pan.
Cook onions for about 2 minutes, then add peppers and remaining salt.
Cook vegetables for another 2–3 minutes until slightly tender but still crisp.
Return chicken to the pan and mix everything together.
Squeeze fresh lime juice over the top and serve the easy chicken fajitas recipe in warm tortillas.