In a large bowl, stir together the cream cheese, sour cream, cottage cheese, half of the mozzarella, Italian seasoning, garlic powder, onion powder, and a pinch of salt and pepper until smooth and creamy.
Lightly spray your slow cooker with nonstick spray.
Spread a thin layer of marinara sauce across the bottom of the crockpot.
Add half of the uncooked tortellini in an even layer.
Spoon half of the creamy cheese mixture over the tortellini and spread it out gently.
Top with half of the browned sausage, then pour half of the remaining marinara sauce over the top.
Repeat the layers — tortellini, creamy cheese mixture, sausage, and marinara — just like a lasagna.
Sprinkle the remaining mozzarella and all of the Parmesan evenly over the top.
Cover and cook on low for 4–5 hours, or until the tortellini are tender and everything is hot, melty, and bubbly.
Garnish with chopped parsley and basil before serving for a fresh, colorful finish.