Place the stock into a medium saucepan and place over a medium heat. Bring to a simmer, and then remove the pan from the heat and cover with a lid to keep hot.
Heat 2 tbsp of the olive oil in a large pan over a medium heat. Add the chicken pieces and fry for 4-5 minutes or until the chicken has browned on all sides. Transfer the chicken to a bowl and set aside.
Add the remaining oil to the same pan and fry the onion, garlic and bacon for 2 minutes or until the onion has softened. Add the rice and mushrooms and stir for a further 1-2 minutes.
Pour in the wine and simmer for 5 minutes or until the liquid has almost completely evaporated. Place the chicken back into the pan, and add a ladle of stock and stir until the rice absorbs all the liquid. Continue to add one ladle at a time, stirring constantly to ensure each ladle of stock is absorbed before adding another.
Once the rice is just cooked and all the stock has been absorbed, remove the pan from the heat and stir in the butter and parmesan cheese, and season with salt and pepper. Cover the risotto with a lid and allow to sit for 2 minutes