Start by heating a skillet over medium-high heat. Add the ground beef and chopped onion, stirring occasionally for about 5 minutes until the meat is well-browned and the onion is translucent. Incorporate minced garlic, dried basil, and parsley into the mixture, cooking for an additional minute until fragrant.

Carefully move the browned meat mixture into the slow cooker. Pour in the canned diced tomatoes, marinara sauce, and low-sodium chicken broth. Stir everything together well, ensuring the meat and sauce blend evenly.

Cover the slow cooker, setting it to low and allowing it to cook for 6 hours. If you're pressed for time, you can set it to high and cook for about 3 hours instead.

Once the cooking time is up, switch the slow cooker to high heat and add the dry pasta, stirring until each piece is well coated and submerged in the sauce. Cook for an additional 15 minutes, then check the pasta’s doneness.

After the pasta reaches your desired tenderness, sprinkle a generous layer of shredded mozzarella cheese on top of the cooked ziti. Cover the slow cooker and let it sit for 3-5 minutes, allowing the residual heat to melt the cheese.