Over medium-high heat, spray a skillet with cooking oil or drizzle in about a teaspoon. Squeeze the sausage out of the casing and into the skillet. Use a potato masher or wooden spoon to crumble the sausage. Once the sausage is cooked through remove it from the skillet and onto a plate lined with paper towels to soak up any excess grease.

Add a tablespoon olive oil to the skillet along with the diced onion and cubed butternut squash. Season with salt and pepper. Cook the vegetables over medium heat stirring frequently.

When the squash is tender, approximately 8-10 minutes, add garlic, rosemary, nutmeg, and red pepper flakes. Cook another minute and then pour in the chicken broth. Scrape up any of the brown bits from the bottom of the skillet then stir in the gnocchi and kale.

Cover the skillet with a lid and simmer over medium-low heat until the gnocchi is tender, about 5 minutes. Remove the lid and stir in the sausage. Taste for seasoning. Sprinkle the mozzarella over the top of everything and cover with the lid again. Cook for a couple more minutes or until the cheese is melted. Serve immediately.