Make the pico de gallo: finely chop about 1 cup ripe tomatoes and 1/2 small red onion, season with salt and squeeze over fresh lime juice; refrigerate to marinate while you prepare the fajitas.
Toss the chicken strips with the fajita or taco seasoning in a bowl until evenly coated.
In a separate bowl, combine the sliced pepper and thickly sliced red onion, drizzle with olive oil, season with salt and pepper, and toss to coat.
Preheat the air fryer: set one basket to 200°C (for vegetables) and the other to 180°C (for chicken) if using a dual-basket unit; otherwise preheat a single air fryer to 180°C–200°C as space allows.
Place the seasoned chicken in the preheated basket set to 180°C and cook for 12 minutes, or until the internal temperature reaches 75°C (165°F) or the meat is no longer pink.
Cook the peppers and onions in the 200°C basket for about 15 minutes, shaking or tossing once halfway, until softened and slightly charred.
Assemble each tortilla: spread a spoonful of yoghurt or sour cream, add a few chicken strips, top with cooked peppers and onions, spoon on pico de gallo, sprinkle grated cheese, add sliced pickled jalapenos, and garnish with small coriander sprigs.
Roll and secure each fajita with a small skewer, lightly spray with olive oil, and air fry at 180°C (350°F) for 5 minutes to crisp the outside.
Serve immediately with guacamole if using.
