Add the Italian sausage links, sliced bell peppers, sliced onion, and minced garlic to the slow cooker.
Pour in the crushed tomatoes, then stir in the oregano, basil, chicken broth, salt, and black pepper.
Cover and cook on low for 6 to 7 hours until the sausages are fully cooked and the vegetables are soft.
About 15 minutes before serving, cook the rigatoni in a large pot of salted boiling water according to package directions. Drain the pasta.
Remove the sausages from the slow cooker and slice them into rounds. Return the slices to the sauce and stir to combine.
Add the drained pasta to the slow cooker and toss everything together until the pasta is coated with sauce.
Serve portions in bowls topped with grated Parmesan cheese.