PREP: If you are using the oven, preheat it to 400 degrees F. If grilling, prepare the grill by heating to medium-high heat (425-450 degrees F.) Tear off four sheets of heavy-duty foil and lightly spritz with cooking spray. If you aren't going to be doing this meal in foil packs (See Note 1), line a large sheet pan with parchment paper and set aside.
PREP VEGGIES: Cut the chicken sausage into coins and then in quarters. Cut the potatoes (no need to peel them) into 4-8 pieces depending on the size; you want small bite-sized pieces, under 1-inch in size. Add diced sausage and potatoes to a large bowl.
SEASON: Drizzle in 2 tablespoons of oil and all of the seasonings (paprika, garlic powder, Italian seasoning, and salt and pepper). Add salt and pepper to personal preference, I add 1 teaspoon fine salt and 3/4 teaspoon pepper. Toss everything together until well combined.
DIVIDE: Divide the mixture evenly among the four prepared sheets of foil. Cut the butter into 1-tablespoon pieces and cut each tablespoon into 4 smaller pieces. Add 4 pieces of butter to each foil pack (1 tablespoon total per foil pack). Seal the foil packs tightly so no air escapes. To seal the foil packet, bring the short sides together in the middle and gently fold down to completely seal. Then, roll up the ends (Don't double wrap the foil, or these packs will take longer to cook).
COOK: Grill for 25-35 minutes or until potatoes are fork tender (flip the foil packs at the halfway point; I flip at 15 minutes) To bake foil packs, add foil packs to a sheet pan and bake for 30-35 minutes or until potatoes are fork tender. (See Note 1 for other cooking methods.)
GARNISH: Carefully open the foil pack, watching for steam to be released. Immediately add the grated Cheddar cheese to each foil pack -- 2 tablespoons of cheese per packet. Loosely re-seal the foil so the cheese can melt, and let stand for 2-3 minutes. Open and top with remaining toppings: We like to add cooked and crumbled bacon, 1-2 tablespoons sour cream per packet, and lots of green onions. (If camping, I'd recommend cooking and crumbling bacon beforehand; if eating these at home, you can cook the bacon fresh.)