Begin by boiling the pasta noodles in accordance with the manufacturer's specifications. Once the noodles reach an al dente texture, drain the water and rinse the noodles under cool water. This step ensures that the pasta remains firm. Set aside for later use.

In a large mixing bowl, combine the finely chopped rotisserie chicken, condensed cream of chicken soup, premium sour cream, fresh baby spinach, half of the finely shredded Monterey jack cheese, minced garlic, and half of the French fried onions. It's crucial to ensure a thorough mix, guaranteeing all elements integrate appropriately.

Incorporate the precooked pasta noodles into the mixture. Ensure an even distribution of the pasta within the mixture.

Prepare a 3-quart casserole dish or a 9x13-inch baking dish by lightly coating it with a non-stick cooking spray. This will prevent sticking and facilitate easier serving post-cooking.

Carefully transfer the mixed ingredients into the prepared baking dish, ensuring a smooth and even spread.

Garnish the top layer with the remaining half of the Monterey jack cheese and French fried onions. Distribute them uniformly across the surface.

Preheat the oven to a temperature of 350°F (175°C). Once reached, insert the dish into the oven and bake for a duration of 40-45 minutes.