What do you do?
Judges, feel free to discuss this scenario on Judge Apps!
[expand title=Answer]This scenario does not fall under ‘Drawing Extra Cards’. As people mentioned in the discussion, it is practically impossible to look at multiple cards without holding them in your hand. By this logic calling the cards taken off the top of the deck is completely legal.
When accepting the above paragraph, the next thing is looking for what is going wrong first. In this case that would be playing a land during the resolution of the spell, a clear Game Rule Violation. Once we reach this conclusion, we also exclude the possibility of this being Drawing Extra Cards.
This leads us to the next pitfall. The first thing we do when handling a GRV is looking if any of the partial fixes are applicable. The partial fix for objects that are changing zones and end up in the wrong zone is not, because had the spell been resolved correctly the cards would not have changed zones at any time. That partial fix only applies to objects which were supposed to be moving from zone A to zone B, but moved to zone C instead.
We are left with GRV and rewind or leave the game state as is. Rewinding a draw for a tapped out opponent is far less disturbing than allowing a player to play on with 5 extra cards in hand so we rewind to the point where the game was last in a legal state which is when Andy was looking at the 7 cards, so we return a random card to top for Nathan, tap him out again, return the played land to Andy’s hand and we are ready to go.
To sum it all up, the proper Infraction is a Game Rule Violation, which comes with a warning. There are no relevant partial fixes, so the solution is to (with HJ permission) rewind to the point in the spell’s resolution when Andy is looking at all 7 cards, since that is the last time the game state wasn’t broken. A failure to maintain game state penalty for Nathan is also appropriate.[/expand]