Cook the fettuccine according to package instructions until al dente. Reserve 1 cup of the cooking water, drain, drizzle with olive oil to prevent it from sticking, and reserve.
Cook the bacon in a large skillet until brown and crispy. Chop and reserve
Melt one tablespoon of butter in the same skillet and reheat the shredded chicken until brown. Transfer to a plate and keep warm.
Add two more tablespoons of butter to the skillet and saute the minced garlic for about 30 seconds. Pour in the white wine and cook until reduced by half.
Pour in the chicken broth, cream, sun-dried tomatoes, Italian seasoning, red pepper flakes, and parmesan cheese. Cook until thickened, about 4 minutes.
Return the chicken to the skillet and add the spinach and cooked pasta. If you feel the sauce is too thick, add the reserved pasta cooking water a little at a time until you reach the desired consistency.