Turn on the Instant Pot using the "Saute" function. Once the liner is hot, add the bacon and stir frequently to keep it from sticking. Cook for 7 to 8 minutes, or until it reaches your desired crispiness. Transfer the bacon to a paper towel-lined plate using a slotted spoon, press "Cancel," and wipe the liner clean.

Return the liner to the pot and press "Saute." Once hot, add the oil and diced chicken. Sprinkle with garlic powder, salt, and pepper, and cook for 4 to 5 minutes, stirring occasionally, until all sides are lightly browned. The chicken does not need to be cooked through. Remove the chicken and press "Cancel."

Spread the pasta into an even layer in the liner and pour in the broth. The broth should just come over the top of the noodles. Add a splash more if needed. Place the chicken on top of the pasta in an even layer. Close the lid, set the valve to "Sealing," and press the Pressure Cook (Manual) button. Set the time to 5 minutes.

When the timer goes off, carefully open the valve for a quick release. Remove the lid. If there is any residual liquid in the bottom of the liner, drain it off before adding the remaining ingredients.

Add the ranch dressing, cheese, and cooked bacon, reserving some bacon for garnish. Stir to combine and serve hot, topped with extra cheese, bacon, and green onions.