Heat olive oil in a large deep skillet or pot over medium heat.
Add the Italian turkey sausage and cook, breaking it up with a spoon, until browned and cooked through, about 5-7 minutes.
Add the chopped onion and cook until softened, about 3 minutes.
Stir in the minced garlic and cook for 1 minute until fragrant.
Pour in the diced tomatoes with their juices, chicken broth, and heavy cream. Stir to combine.
Add the dried Italian seasoning and crushed red pepper flakes. Season with salt and black pepper to taste.
Bring the mixture to a simmer.
Add the potato gnocchi to the pot and stir gently to submerge them in the sauce.
Cover and cook for 3-5 minutes, stirring occasionally, until the gnocchi float to the surface and are tender.
Stir in the fresh baby spinach and cook until wilted, about 2 minutes.
Remove from heat and stir in the grated Parmesan cheese until melted and combined.
Adjust seasoning with additional salt and pepper if needed.
Serve immediately.