Tape cannot be used on Shabbos. Similarly, one should not stick a sticker as it is an extension of ‘sewing.’
A sticky tab on a diaper may be used when putting a diaper on. As opposed to an adhesive which one plans on putting on for a limited amount of time which is forbidden, a diaper is intrinsically a temporary act (diapers cannot stay on a baby for very long). However. after using the diaper one should not use the tabs to wrap the diaper as they are being placed to last permanently.