Prepare all of the ingredients. Start water boiling for pasta.
In a frying pan over medium high heat, add bacon. Cook until crispy and remove to paper towel covered plate.
In a sauce pan over medium high heat, add chicken and garlic. Cover with water and boil for 15 minutes. Remove from water and chop.
Add pasta to boiling water. Cook as directed on package. Drain in a colander and rinse with cool water to arrest cooking process. Return to pot.
In a sauce pan over medium heat, add butter and garlic salt. Once melted add flour and mix together. Cook for 3 minutes then add chicken broth. Cook for 3 minutes and add green chilies. Cook another 2 minutes then whisk in heavy cream. Cook for 2 minutes and add cheese (one handful at a time) until completely melted.
Pour cheese sauce over cooked pasta. Add chicken and half of bacon. Stir until fully combined. Serve in a shallow pasta bowl and garnish with remaining bacon and scallions.