Cook tortellini according to package directions. Reserve 1 cup of the pasta water for later.
Meanwhile, cube the chicken into 1 inch pieces, dice the onion, slice the mushroom, cut the tomatoes in half, mice the garlic, and chop the basil.
Heat 2 Tbsps. of olive oil in a large skillet and pan sear the chicken until fully cooked and browned. Salt and pepper them while they cook with ½ tsp of each. Once the chicken obtains a golden color, remove and set aside in a bowl. Cover to preserve moisture.
In the same skillet, add the remaining 2 Tbsps. of olive oil and bring to medium heat. Add the onions and allow them to sauté until tender and translucent in color.
Add in the sliced mushrooms, minced garlic and sauté until tender.
Add the half and half, cream cheese, pasta water, black pepper, salt, pesto, and tomatoes. Mix well to melt the cheese. Cover to cook on low for 2-3 minutes to allow the sauce to thicken up.
Next, add in the chicken, parmesan cheese, fresh basil and fresh spinach. Mix and cover to cook again on medium-low heat for 2-3 minutes.
Finally, add in the cooked tortellini and mix everything together to coat the tortellini with the sauce. Cook for another 2-3 minutes and then remove to serve.
Garnish with some basil leaves and shaved parmesan cheese.