1. Place chicken in the slow cooker. Sprinkle the ranch mix on top of the chicken and a half cup barbecue sauce on top. Pour the broth on top.
2. Cover the crockpot and cook on low for 5 to 6 hours or high for 3 to 4 hours.
3. Remove the chicken from the crockpot and shred it. Mix in remaining the barbecue sauce.
4. Whisk in the cornstarch mixture into the drippings in the crockpot. Add in the cream cheese and cheddar cheese and whisk until smooth.
5. Stir in uncooked pasta and top with the shredded chicken.
6. Cover and return slow cooker to high for 30 to 60 minutes until pasta fully cooked, stirring 2 to 3 times.
7. Add additional liquid 1/4 cup at a time if needed for pasta to fully cook.
8. Serve pasta immediately topped with green onions and drizzle with barbecue sauce.