Heat olive oil in a large pot or Dutch oven over medium-high heat. Season chicken pieces with salt and pepper, then add to the pot and cook for 5-6 minutes until golden brown and cooked through. Remove chicken and set aside.
In the same pot, add minced garlic and cook for 30 seconds until fragrant. Add sun-dried tomatoes, Italian seasoning, and red pepper flakes (if using), and stir for another minute.
Pour in the dry pasta and chicken broth. Stir well, scraping up any browned bits from the bottom of the pot.
Bring to a boil, then reduce heat to medium and simmer uncovered for 10-12 minutes, stirring frequently, until pasta is almost al dente.
Reduce heat to low and stir in the heavy cream. Let simmer for 2-3 minutes until the sauce thickens slightly.
Add the chopped spinach and cooked chicken back to the pot. Stir until the spinach wilts, about 1-2 minutes.
Remove from heat and stir in Parmesan cheese. Taste and adjust seasoning with salt and pepper as needed. Garnish with fresh basil and serve immediately.