Preheat oven to 200 degrees C. Place turkey mince in a large, deep frypan. Cook over medium high heat until evenly brown. Stir in spring onions, taco seasoning mix, water, diced tomatoes with juice and chilli. Reduce heat to medium.
In a medium bowl, mix together ricotta and eggs. Place 2 tortillas in the bottom of a 20x30cm pan. Spread 1/4 of the ricotta mixture on tortillas. Spoon 1/4 of the meat mixture over the cheese. Repeat layers until all is used up.
Bake in preheated oven for 20 minutes, or until sauce is bubbly. In a small bowl, mix together sour cream and salsa. Serve in a bowl on the side.