In a large pot over medium heat, drizzle in olive oil and add Italian sausage. Cook until browned and crispy, about 8-10 minutes. Transfer to a plate and set aside.

In the same pot, add diced onion and cook for 5-6 minutes until softened. Add minced garlic and dried oregano, sauté for 1 minute.

Return sausage to the pot and add cubed potatoes, bay leaf, thyme, salt, and pepper. Pour in chicken stock and bring to a simmer.

Once simmering, reduce heat to low, cover partially, and let simmer for about 15 minutes until potatoes are fork-tender.

Remove bay leaf and thyme. Stir in heavy cream or half-and-half and chopped kale. Cook uncovered for 5 minutes until kale wilts.

Adjust seasoning if needed, add nutmeg, and serve hot with grated Parmesan cheese on top.