1.In a frying pan, heat half the oil on high. Saute onion and garlic 1-2 minutes, until tender.
2.Add chicken and chilli. Cook, stirring, 1-2 minutes. Transfer to a bowl. Stir in cheeses, and season to taste.
3.Heat tortillas following packet instructions. Spoon 1/4 cupfuls of chicken mixture down the centre of each tortilla. Roll up firmly.
4.In a bowl, roughly mash avocado with lemon juice and season to taste.
5.Heat remaining oil in a frying pan on medium. Cook tortilla rolls 2-3 minutes, turning, until golden. Drain on paper towel. Serve with avocado and salsa.