Mix together the smoked paprika, chilli, cumin, cayenne and garlic powder. Rub half into the chicken pieces. Heat 1 tbsp of the oil in a large deep frying pan and cook the chicken for 5-6 minutes until golden all over and almost cooked. Remove with a slotted spoon and set aside.
Meanwhile, cook the pasta according to the instructions on the packet. Drain well and set aside, reserving a little of the cooking water.
Heat the remaining oil in the pan and cook the onion along with the remaining spice mix for 3-4 minutes until tender. Season, then add the peppers and cook for another 3-4 minutes until just soft.
Add the chicken back to the pan along with the tomato puree. Cook for 2 minutes, then stir in the cooked pasta, salsa and sour cream. Heat through, and if the sauce needs loosening, add a little of the reserved pasta water until you reach a desired consistency. Sprinkle over the cheese to serve.