Squeeze the juice of lemon over chicken, sprinkle salt and red chilli powder and mix well.
Heat the oil from bhuna masala in a non-stick pan, add chicken and saute on high heat till done. Transfer chicken into a bowl. Heat the tortillas on a non-stick tawa and set aside on a plate.
Put onion, tomato and capsicum in the same pan. Add bhuna masala and mix well and cook for 2 minutes. Place 1 tortilla on the tawa, spread the chicken over it.
Sprinkle half the processed cheese and mozzarella cheese over the chicken. Place another tortilla over it and press lightly.
Spread the vegetable mixture over the 2nd tortilla. Sprinkle the remaining processed cheese and mozzarella cheese over them. Place the 3rd tortilla over and press lightly.
Drizzle a little oil all around and over the last tortilla and let it cook. When the underside is crisp, turn over the entire thing carefully and let the other side cook similarly.
Remove the quesadilla onto a plate and cut into 4-6 triangles. Arrange them on a serving plate, garnish with strips of green and red capsicums and serve immediately.