Is there a way to completely disable nicknames? I'm trying to change up my chat formatting

I've tried:

• using /nick ** off but it crashes after about 2 minutes because of so many players
• changing {DISPLAYNAME} it chat formatting to {USERNAME} but apparently that doesn't work in the chat format section

Use the disabled-commands found in the config file and put the nick command to the list.
https://github.com/EssentialsX/Essentials/blob/2.x/Essentials/src/config.yml#L157

Will this get rid of players nicks?

Yes, the players still get the setted nicknames. But the command will be disabled,

That won't remove existing nicknames, no. You could try and write a simple python script to edit the playerdata files and remove the nicks but the only way to do it through Essentials (afaik) is to use the /nick ** off function.

That won't remove existing nicknames, no. You could try and write a simple python script to edit the playerdata files and remove the nicks but the only way to do it through Essentials (afaik) is to use the /nick ** off function.

Yeah /nick ** off just crashes after like 2 minutes not removing all nicks
If I could make only the username display in chat instead of nick it would not be a problem

That won't remove existing nicknames, no. You could try and write a simple python script to edit the playerdata files and remove the nicks but the only way to do it through Essentials (afaik) is to use the /nick ** off function.

Yeah /nick ** off just crashes after like 2 minutes not removing all nicks
If I could make only the username display in chat instead of nick it would not be a problem

If using EssentialsChat, use {USERNAME} instead of {DISPLAYNAME}.

If using EssentialsChat, use {USERNAME} instead of {DISPLAYNAME}.

{USERNAME} does not currently exist as a placeholder for EssentialsXChat. Available placeholders are:

{DISPLAYNAME} 
{MESSAGE} 
{GROUP}
{WORLD} 
{WORLDNAME} 
{SHORTWORLDNAME} 
{TEAMPREFIX} 
{TEAMSUFFIX} 
{TEAMNAME}
{PREFIX}
{SUFFIX}

PR #2781 would add this functionality, but it hasn't been merged yet.

While this doesn't completely solve your issue, the PR has been merged and you can now use {USERNAME} in the chat format with EssentialsX versions 2.17.1.17 and above.