While you have time before starting the slow cooker, cook the bacon in a skillet over medium-high heat until crispy, about 8-10 minutes. Transfer to a paper towel-lined plate and crumble into roughly 1/2-inch pieces once cooled. In a small bowl, combine salt, pepper, garlic powder, onion powder, and smoked paprika—this pre-mixed seasoning blend will distribute evenly throughout the chicken. I like to do this prep work first so the bacon is ready to go when you need it later, and you're not scrambling at the end.
Place the chicken breasts in your crockpot and sprinkle evenly with the seasoning blend from Step 1. Pour in the chicken broth, making sure the liquid covers most of the chicken. Cover and cook on LOW for 6-8 hours until the chicken is completely tender and shreds easily with a fork. The long, gentle cooking ensures the chicken stays juicy and absorbs the savory broth flavors.
About 30 minutes before the chicken finishes, bring a large pot of salted water to a boil and cook the pasta according to package directions until al dente. Drain and set aside. Cut the cream cheese into 1-inch cubes so it melts smoothly and evenly into the sauce without clumping. In a small bowl, whisk together the ranch mix with 1 cup of water to create a thin seasoning liquid.
Once the chicken is fully cooked and tender, remove it from the crockpot with tongs and place on a cutting board. Shred it into bite-sized pieces using two forks. Return the shredded chicken to the slow cooker with the broth, then add the cooked pasta from Step 3, cream cheese cubes, ranch mixture from Step 3, and 1 cup of the cheddar cheese. Stir well to combine everything evenly, making sure the cream cheese starts to incorporate into the warm liquid. I find that stirring thoroughly at this point helps prevent lumps and creates a smoother, more cohesive sauce.
Turn the slow cooker to HIGH and cook uncovered for 20-30 minutes, stirring occasionally, until the sauce is thick, creamy, and all the cream cheese is fully melted. The higher heat helps the sauce reduce slightly and become more cohesive while keeping everything warm and properly mixed throughout.
Transfer the pasta to a serving bowl or plates. Top generously with the crispy bacon from Step 1, remaining 1.25 cups of shredded cheddar cheese, and sliced green onions. Cover the dish loosely with foil and let sit for 2-3 minutes so the residual heat melts the cheese slightly while you plate everything. Serve hot while the sauce is still creamy and the cheese is warm.