Pop the chicken, peppers and onions on a large roasting tray with the 2 tbsp fajita seasoning and oil. Roast for 25 minutes at 200°C, stirring occasionally.
Meanwhile, mix everything together for your dip and set aside.
Brush your butter across the base of a sheet pan. Lay 7 tortillas in, as per the video. Put in half your cheese, half your chicken, all of your chips, then the rest of the chicken and cheese. Fold over the tortillas, then lay over a sheet of greaseproof and weigh down with a heavy tray.