In a large pot, cook pasta according to package instructions (ensure you salt the water appropriately, about 1 teaspoon per quart of water used)

In a small saucepan, combine the chicken broth and milk and warm gently but do not boil. Set aside.

In a large saute pan, heat the oil over medium heat, add the flour and stir to form a roux and cook over medium heat for 1 to 2 minutes. Do not allow the roux to brown.

Add the black pepper, and broth/milk mixture to the roux and whisk briskly until smooth. Continue heating gently until thickened, then remove from heat and add the Parmesan cheese.

When pasta is finished cooking, drain and reserve 1 cup of pasta water

To assemble dish, combine cheese sauce with pasta, spinach, and chicken. Stir to combine and very slowly add small amounts of the reserved pasta water, only if needed, to thin sauce.