In a frying pan with oil, cook and stir the onions, chorizo, paprika, garlic and oregano in frying pan until onions are softened. Add the chicken and fry until just cooked, no longer pink in the middle, add tomato sauce and heat until thickened.
Cook fresh lasagne sheets by placing in boiling water for 5 minutes. Drain.
Preheat the oven to 200 C / Gas 6.
Put a very shallow layer of the tomato and chicken sauce into the oven dish then put one layer of the sheets down. Pour the chicken and sauce mixture over. Put a layer of lasagna sheets down and pour 1/2 the white sauce over and repeat again then sprinkle mozzarella cheese over the top.
Bake in the oven for 30 minutes until piping hot.
This recipe calls for 6 fresh lasagne sheets but you should use enough to make 3 layers in your lasagne. Dry lasagne sheets should also work fine, cook according to instructions on packet.