Bring a large pot of well-salted water to the boil. Cook the rigatoni according to packet instructions. Before draining, reserve ½ cup of pasta water, then drain well. 

While the water is coming to the boil, heat a large saucepan over medium-high heat. Add the pancetta and cook, stirring, for 3 minutes until the fat has rendered and the pancetta is starting to crisp. 

Add the onion, garlic and oregano and cook for a further 3 minutes until softened and lightly golden. 

Add the tomato paste and stir through for 1 minute. Pour in the cream and bring to the boil. 

Add the chicken and basil leaves. Reduce the heat to a simmer and cook for 10 minutes, stirring occasionally, until the sauce has thickened. Season with salt and freshly cracked black pepper to taste. 

Add the drained pasta to the sauce and toss to combine. If the sauce is too thick, loosen with a splash of the reserved pasta water. Serve topped with pecorino.