Tex-Mex
Mix 2 tbsp of the oil with the lime juice, chili powder, cumin, paprika, garlic, oregano and salt, then toss the chicken in the mixture.
Leave the chicken to marinate for 30 minutes.
Heat a large cast-iron skillet over high heat until very hot, add the chicken in a single layer and sear for 5-6 minutes, turning once, until browned and cooked through.
Transfer the chicken to a plate and keep it warm.
Add the remaining oil, the peppers and the onion to the skillet and cook for 5-6 minutes, stirring often, until charred at the edges but still crisp.
Return the chicken to the skillet, toss for 1 minute and sprinkle with the cilantro.
Serve sizzling from the pan with warm tortillas, salsa and guacamole on the side.