Motive. The classic third pillar of any mystery, alongside means and opportunity. If someone did something, they need to have the ability to do it, the chance to do it, and a reason to do it.
If you're designing an adventure scenario around the heroes figuring out a crime, or even just a strange thing that someone did, it's vital that you give some thought to setting up answers to the questions of what these three things are. Make sure your NPC perpetrator had the ability to do the thing, the time to do the thing without being noticed, and a reason for doing.
The reason is probably the most important part. What plot does it fit into? What other things does it lead to? Should the heroes be worried? Yes, they should!
Commentary by memnarch (who has not seen the movie)
I mean, all that we have left to confirm Nute did the edits is for him to program a message saying "It was me, I broke the star charts" and broadcast it to the Galaxy. No one else has the motive or the capability that we've heard about to do something like that. Heck, even for the physical copies that exist, he'd just get some minions, traitors, or traitorous minions, to handle that part and there's no shortage of those to be found in the Galaxy.
Speaking of minions though, I'm really curious to see how Snoke's motivations are going to line up with this part of the Nute Gunray plot thread. Snoke wants to find Ahch-To, which Nute caused to be hidden. Are we looking at a future betrayal of some kind by Snoke and Kylo perhaps? That could handily resolve the whole digital bad guy problem where we already know he can't show up in the movies. Heck, we could even have a few more Kylo-temper-tantrum scenes show up and have those be a part of vanquishing Nute for good while still having Kylo be on Team Bad Guy.
Luke: Why are you defragging yourself?
R2-D2: I’ve been going over the differences between the the standard star charts and the map to Ahch-To that you left with Lor San Tekka.
[SFX]: < bebop jewhree ziku-ting cheep whree bezioo-doodle-doip >
Luke: Ah. So you found the errors?
R2-D2: Not just the errors. We think we know who did it. Nute Gunray. But we don’t know why. Do you?
[SFX]: < boobiwhree bebloop deep doing-cheep boodeep ping ping >
GM: Don’t look at me.
Luke: Maybe the ancient Jedi texts. If he knew I’d brought them here.
R2-D2: Assume Nute knows everything.
[SFX]: < doing-cheep deep biwhirdlezip >
Luke: But why would he want to hide them.
R2-D2: Midi-chlorians are organic. And they wield great power. Nute is now digital...
[SFX]: < babading ding bzzt bespip doing-cheep cheep >
R2-D2: He’s afraid of the Force.
[SFX]: < oogoo spip >
Luke: Given how Obi-Wan introduced me to it, I don’t blame him.