Melt 2 tablespoons butter in a large Dutch oven over medium heat. Add 1 small chopped onion and sauté for 3-4 minutes until softened and fragrant.
Add 4 cloves minced garlic and cook for 1 minute until aromatic. Stir in 1/2 cup roughly chopped sun-dried tomatoes and cook for 1 minute more.
Sprinkle 1 tablespoon Italian seasoning over the mixture and stir well to combine.
Pour in 1/2 cup white wine and stir, simmering until reduced by approximately half, about 2-3 minutes.
Add 4 cups chicken stock and 1 cup heavy cream to the pot. Bring to a boil, then reduce heat to medium for a strong simmer.
Add 3/4 cup ditalini pasta and stir well, making sure to scrape the bottom of the pot to prevent sticking. Cook for 10 minutes, stirring regularly and scraping the bottom every 2-3 minutes.
While pasta cooks, generously season both sides of 1 pound chicken breasts with salt and pepper.
Heat 1 tablespoon oil in a small skillet over medium-high heat. Cook chicken for 3-5 minutes per side until firm and cooked through (internal temperature should reach 165°F).
Remove chicken from heat and let rest until cool enough to handle, about 2 minutes. Chop into bite-sized pieces.
Reduce soup heat to low. Stir in 1 cup freshly grated Parmesan cheese until melted and well combined.
Add chopped chicken to the pot and let flavors blend for 2-3 minutes.
Adjust seasoning to taste with salt and black pepper.
Stir in 2 cups fresh chopped spinach and cook until just wilted, about 30 seconds.
Ladle into serving bowls and top with 1 tablespoon fresh sliced basil and additional Parmesan, as desired. Serve immediately.