Heat the oil in a heavy 4 to 6-quart pot over medium flame. Add the onions, garlic, and sausage; cook, stirring with wooden spoon, until the sausage renders out some of its fat and the onions are soft.
Toss in the herbs and then the potatoes, stir that around for a minute to coat in the oil. Pour in the chicken broth and bring up to a simmer.
Add the kale, season with salt and pepper. Cover and simmer for 10 minutes until the potatoes are nearly tender.
Uncover the pot and add the clams; simmer, covered, for 15 minutes until the clams open. Add the fish and continue to cook for another 3 to 5 minutes until the fish is cooked. Garnish with chopped parsley and drizzle with olive oil.