Drain 3 tbsp oil from the sun-dried tomato jar into a large pot. Chop the sun-dried tomatoes and set aside.
Heat a large pot over medium-high heat. Add chicken sausage and onions. Cook for 6–8 minutes, breaking up the sausage, until browned and the onions are softened.
Add garlic, celery, carrots, Italian seasoning, garlic powder, chili powder, salt, and pepper. Cook for 4–5 minutes, stirring occasionally.
Add chicken stock and bring to a simmer. Cook for 10–15 minutes, until carrots and celery are tender.
Add white beans, sun-dried tomatoes, and spinach. Cook for 2–3 minutes, until the spinach is wilted and beans are warmed through.
Reduce heat to low. Stir in heavy cream, Parmesan, lemon juice, and lemon zest. Cook for 2–3 minutes, stirring, until warmed through. Do not boil.
Taste and adjust salt and pepper as needed.
Top with fresh parsley and serve.