Cook the penne pasta according to package instructions.
In a large mixing bowl, combine the shredded chicken and ranch seasoning.
In a saucepan over medium heat, combine the cream cheese and chicken broth, stirring until smooth.
Once the mixture is smooth, add garlic powder and pepper, stirring to combine.
Fold in shredded chicken and cooked penne pasta until evenly coated.
Add shredded cheddar cheese and stir until melted and creamy.
Remove from heat and garnish with chopped green onions before serving.