Step 1

Bring a large pot of heavily salted water to a boil. Add the spaghetti and cook, about 10 minutes, until just shy of al dente. Reserve about ½ cup of the pasta water. Drain, toss with 1 tablespoon of the olive oil and set aside.

Step 2

Preheat the oven to 350°F. Spray a 13x9-inch baking dish with nonstick spray. Set aside.

Step 3

Heat the remaining tablespoon of olive oil in a large dutch oven over medium-high heat. Add the onion and bell pepper along with a pinch of salt and pepper. Saute for about 5 minutes, until the onion is translucent and soft.

Step 4

Add the diced tomatoes with chilies and cook until most of the liquid has evaporated, about 5 minutes.

Step 5

Add the mushroom and chicken soup and chicken stock. Bring to a simmer.

Step 6

Add the cheeses and stir in until melted and the sauce is creamy. Add the chicken. Taste and season with salt and pepper as desired.

Step 7

Stir the cooked spaghetti into the sauce. If needed, use some of the reserved pasta water to thin the sauce and bring the mixture together.

Step 8

Transfer to the prepared baking pan.

Step 9

Bake for 30-40 minutes, until the sauce is bubbly and the top is golden. Serve hot.