One Pan Chicken Fajitas

• 400 g chicken thigh fillets, fat trimmed, sliced into 1 cm strips
• 3 red capsicum (pepper), sliced into thin strips
• 1 red onion, thinly sliced
• 28 g fajita spice mix
• 8 wholegrain tortillas
• 2 avocado, ripe, cut into 1 cm cubes
• 1 bunch coriander (cilantro), leaves
• 2 limes, juiced