Air carrier First Officer reported wingtip of wide body aircraft passed over aircraft while parked in pad at ORD. Crew notified ATC.

Narrative

While taxiing from terminal X toward rwy 28C; O'Hare ground instructed us to pull into pad A" (alongside taxiway TT) to await our Estimated Departure Clearance Time (EDCT). Captain taxied into pad A and turned the aircraft east; so it was pointing at about a 45° angle within the pad.As he taxied into the pad; I noticed the dashed yellow line painted down the middle of the pad; parallel to twy TT. It occurred to me that it might be a line that parked aircraft are supposed to be positioned behind; or perhaps a centerline where the nose wheel should be positioned. The captain positioned the nose wheel on this dashed line prior to turning 45° toward the taxiway; so I figured it must be a marking similar to the markings on device pads. After we parked in the pad; one or more aircraft taxied by on twy TT. Then we heard ground instruct Aircraft Y to taxi on twy TT. As Aircraft Y approached our position; it became clear to both of us that there was insufficient clearance between the nose of our aircraft and the right wingtip of the approaching aircraft. I said "they re going to hit us!" The captain gestured to the captain of Aircraft Y to stop. A collision appeared imminent as Aircraft Y continued taxiing. I saw the right wingtip of Aircraft Y pass over top of our aircraft. There was significant overlap - I would estimate more than 10 feet of Aircraft Y wing was overlapping the nose of our aircraft. The wingtip of Aircraft Y passed so far behind our cockpit that the wingtip disappeared from view.After Aircraft Y was clear; I radioed ohare ground; explaining there was insufficient clearance between us and aircraft taxiing by on twy TT. ground had us reposition to twy B; short of twy G. The reminder of the taxi and the flight was uneventful."