How can you fly at 0kts without stalling?
No, stalls can occur at any airspeed, attitude, or load factor.  All that is needed is to exceed the critical angle of attack and you have stalled the airplane.

Some places this can occur and does happen if mishandled by the pilot is at the top of inside loops, where the airplane can come very close to a zero airspeed if it's done wrong.  Another place this does occur is a hammerhead stall where the stall occurs in the vertical, just as the aircraft is at or comes very close to zero airspeed.