Layer the base: Place chicken in the slow cooker. Sprinkle with ranch seasoning, garlic powder, onion powder, pepper, and smoked paprika if using.
Add the creamy elements: Scatter cream cheese cubes over the chicken. Pour in chicken broth.
Cook low and slow: Cover and cook on Low for 4–5 hours or on High for 2–3 hours, until the chicken shreds easily.
Shred the chicken: Transfer chicken to a cutting board and shred with two forks.
Return shredded chicken to the slow cooker.
Finish the sauce: Stir in heavy cream and 1.5 cups of the cheddar until smooth and melty. Taste and add salt if needed.
Cook the pasta: Boil pasta in salted water until just shy of al dente (about 1 minute less than package directions). Drain well.
Combine: Stir the cooked pasta into the slow cooker until evenly coated in the sauce.
Top and melt: Sprinkle remaining 1/2 cup cheddar over the top.
Cover and let it sit on Warm for 5–10 minutes until the cheese melts.
Finish with crunch and color: Stir in or sprinkle bacon, then garnish with green onions or chives.
Serve: Spoon into bowls and serve hot. Add extra bacon or ranch drizzle if you like.