Layer onions, mushrooms, garlic tomatoes, basil, oregano, and pepper in your slow cooker.
Top with chicken breasts that have been lightly dusted with salt and pepper. Cook on low for 6 hours.
After approximately 5 ½ hours, cook pasta to al dente if you have not done so already.
Remove chicken and shred.
Stir noodles and shredded chicken into the slow cooker and cover with shredded cheese as well as the parmesan. Return cover and cook until cheese has melted.
Meanwhile, spray a small sauce pan with cooking spray. Head over medium heat.
Once hot, add breadcrumbs and toast them, stirring every minute or so. Watch them carefully as not to burn them.
Serve, topping with the toasted breadcrumbs for texture.