Add chicken broth, chicken breast, roasted red peppers, parsley, garlic, salt, oregano, basil and pepper to a 2.5-4 quart slow cooker. Cook on high for 3 hours or low for 6 hours until chicken is cooked through
Remove chicken from the slow cooker and shred with two forks. Place back into the slow cooker.
Whisk together the cream or milk and corn starch. Add to the slow cooker with the pasta and spinach.
Turn to high and cook for 15-20 minutes until pasta is al dente or cooked to desired tenderness (this can take up to 30 minutes). Turn off, stir in cheese and serve immediately.