Prepare the veggies; chop and diced the onion, red chilli, mushrooms, tomato, red and green capsicum. Dice the chicken breast.
Frying pan on high heat with water and add diced chicken, stir-fry for a few minutes, add salt and a good grinding of black pepper until chicken is cooked. Remove from the pan and set aside.
Add the onion and red chilli into the same frying pan. Stir and cook until soften, adding together the mushroom, soy sauce, tomato, red and green capsicum and the cooked chicken, season with salt and pepper. Cook for about five minutes and remove from heat to set aside.
Heat a non-stick pizza or frying or griddle pan over medium heat. Place one tortilla on the pan and add about 1 large tablespoon of the grated cheese on one half of the torilla, top with filling mixture and then sprinkle a little more cheese on top. Fold over to cover toppings.
Cook tortilla on each side for about a minute, or until cheese is melted and tortilla is lightly golden crisp. Transfer pizzadilla to a plate. Repeat with remaining tortillas and toppings. Slice into wedges to serve.