Add more straps and replace nails
Usually the hot water pipes do most of the “talking” because they expand and contract as the water temperature changes inside them. That movement eventually loosens the nails at some pipe straps. The pipes then rub against the floor joists, making that annoying creaking sound. The best way to solve the problem permanently is to add more pipe straps (they’re cheap, so add one per joist) and replace all the existing nails with screws.