Preheat a heavy bottomed pot on a medium to high heat.
Prepare your chicken by cutting into small pieces and pat dry with a paper towel.
When the pot is hot (a small splash of water will dance on the surface) add a good glug of oil and brown the chicken. Once its browned take the chicken out and return the pot to the heat.
Add the chicken stock to the pot and use a flat wooden spoon to get all the flavour off the bottom of the pot (deglazing).
Place the peas, spinach and cashews in the stock and simmer for 10-15 minutes until the cashews are soft.
While the sauce simmers boil a pot of water with another glug of oil, and cook the pasta using the directions on the packet.
Blitz the green pasta sauce using a stick blender (or alternatively transfer to a kitchen blender). Place the chicken back into the pot and heat through.Season to taste with salt and pepper.
Plate up the pasta and top with the chicken and green pesto (top with parmesan cheese if you are using it).