First, check with your BON to see if they have the same criteria. Your BON may further define sleeping on the job. Secondly, just off hand, I would say 'closing your eyes' for a short period of time is going to be considered sleeping on the job if you are supervising patients at the time. You and only you are responsible for being alert and able to do the job you've accepted with the patient load you took report for . If your facility will allow you to take a break, go into a break room and power nap for 15-30 minutes, then great but I would definitely check the policy on that and never, but never, count on that getting to happen. In other words, don't go to work expecting to get to sleep. Our main concern is patient care and safety. If you are not safe to work, then don't go to work. Trust me, I'm not going to have any sympathy for your sleep deprivation if my loved one dies because you were 'closing your eyes for a short period of time'.