Place the chicken breast in the inner pot. Add in four cups of water. Push the pressure cooker setting and set the temperature to HI and set the timer to fourteen minutes. Quick release when done. DON'T DISCARD THE LIQUID.Shred the chicken into big pieces. You don't want a finely shredded chicken. Fry the bacon and drain excess oil. Set aside.
Break the spaghetti into two and put it in the inner pot. Make sure that the spaghetti is not adhering to each other. You can do this by holding the spaghetti on both ends and breaking it in the middle then dropping it in the inner pot.
Add in the water or chicken broth from the chicken breast.
Place the pot in the Instant pot base and cover with a pressure cooker lid. Push the pressure cooker button setting and set the temperature to HI. Set the timer to eight minutes and quick release.
When done, cancel the pressure cooker button setting. Push the saute' button immediately add in ranch dressing and cream cheese, and Velveeta cheese. Mix gently but quickly to melt the cheeses. Mix gently but quickly to melt the cheeses. Transfer the spaghetti immediately to not overcook.