Heat oil in a large skillet add in the chicken season with salt pepper and Italian seasoning. Cook the chicken until it's 90% of the way cooked. Add in the diced onion and continue to cook the chicken until its cooked through and the onion is soft.
Stir in the tomatoes in continue to cook for 2 minutes.
Add in the basil and spinach stir well cook until the spinach wilts down.
Add the Parmesan cheese stir to melt it down and serve.