How can I see the Minecraft user names using NBTEditor?

Those codes (I am referring to the text after player_ or player_server_) are the UUIDs (unique identifiers) of the players.

On Bedrock Edition there seems to be no easy way of getting usernames from UUIDs, at least at the time of writing this answer.

On Java Edition, every Minecraft player has a different UUID which is a randomly generated string. This means that players can change their names multiple times easily.

To get the username of a player in Java Edition from the UUID I would recommend using NameMC (https://namemc.com/).

I have an idea, but it is pretty tedious... What I did was used scoreboard values, and using the scoreboard ID's to find the players ID's (that way you know like this play has "thismuch'money'" you can think, Oh, So-and-so has that much money!) then go to the players part in MCC, (just click on the subfolder called "players" and a list will come up. Scroll down until you find players that actually have health and hunger, and it will show on one of them the ID that you found with the scoreboard. Or, if you know whats in their inventories you could look throught those, but thats even more time wastful......