Cook the pasta in a large pan of boiling water for 12 minutes. Drain and set aside.
Meanwhile, heat the oil in a large, deep frying pan. Add the onion, garlic and chorizo and fry, stirring, for 6-8 minutes until the onion and garlic are soft and golden.
Add the chicken and fry for 5-10 minutes until cooked through with no pink remaining.
Tip the pasta into the pan with the chicken mixture and stir in the crème fraîche and parsley. Squeeze over the lemon juice, mix together and serve immediately.