Preheat your oven to 375°F (190°C). Lightly grease a medium baking dish with the butter and set aside.
Bring a large pot of salted water to a boil. Add the dry rotini pasta and cook according to package directions until just al dente. Drain the pasta well and set aside.
While the pasta cooks, heat the olive oil in a large skillet over medium heat. Add the ground beef and cook, breaking it up with a spoon, until browned and cooked through, about 6 to 8 minutes.
Drain any excess fat from the skillet if necessary, then return the skillet with the cooked ground beef to medium heat.
Stir the ranch seasoning mix, garlic powder, onion powder, salt, and black pepper into the cooked ground beef until the meat is evenly coated.
Pour in the tomato sauce and beef broth. Stir well and let the mixture simmer gently for 3 to 4 minutes to slightly thicken and allow the flavors to blend.
Add the drained sweet corn to the skillet and stir it into the beef mixture until evenly distributed. Let it warm through for 1 to 2 minutes, then remove the skillet from the heat.
In a large mixing bowl, combine the drained rotini pasta with the beef and sweet corn mixture. Stir until the pasta is well coated with the sauce.
Add the sour cream and 1 cup of the shredded cheddar cheese to the pasta mixture. Fold gently until the sour cream and cheese are fully incorporated and the sauce looks creamy.
Transfer the pasta mixture to the prepared baking dish, spreading it out into an even layer.
Sprinkle the remaining 1/2 cup shredded cheddar cheese evenly over the top of the pasta.
Place the baking dish in the preheated oven and bake for 18 to 22 minutes, or until the cheese on top is melted, bubbly, and lightly golden around the edges.
Remove the Cheesy Ranch Rotini Bake with Beef and Sweet Corn from the oven and let it rest for about 5 minutes before serving so it can set slightly and be easier to scoop.