Place a Dutch oven or large pot on medium heat, add in the olive oil and the linguiça.
Saute the linguiça until it's cooked through and crisp around the edges. Use a slotted spoon to remove it from the pan and set it aside.
Add the chopped onion into the pot with the sausage drippings and season with a pinch of salt. Saute for 4-5 minutes, until it's tender and translucent, but not browned.
Add in the chicken stock broth, potatoes, 2/3 of the kale and a pinch of salt and pepper. Reserve the last 1/3 of the kale for later.
After blending the soup, add in the rest of the kale and cooked linguiça. Cover the pot and cook for another 10 minutes, until the kale is tender. Taste the soup, then season with salt and pepper to taste.
Serve hot with a drizzle of olive oil and some crusty Portuguese bread.