This is a cool idea!

Received a crash report with the following text:

The mod Tier Generator (0.2.2) caused a non-recoverable error.
Please report this error to the mod author.

Error while running event tier-generator::on_init()
tier-generator/interface/tierMenu.lua:77: attempt to get length of field 'tier_array' (a nil value)
stack traceback:
tier-generator/interface/tierMenu.lua:77: in function 'update_list'
tier-generator/interface/tierMenu.lua:161: in function 'create_frame'
tier-generator/interface/tierMenu.lua:179: in function 'init'
tier-generator/control.lua:18: in function <tier-generator/control.lua:15>

I have many mods installed: Krastorio 2, Space Exploration, Very BZ, most of Planetfall's mods, a bunch of others that I can list if needed.

What Timing!
I got that crash just as I was starting to try and stress test with Ultracube
I noticed I simply forgot to initialize that global array because I was relying on a function I called a moment later to do it for me.
Will be fixed in the next release.

Awesome, will keep an eye out!

I cleaned up my messy testing and just pushed my fixes.

I still can't guarantee that it'll work with many combinations of mods.
I've been focusing on getting vanilla and minor vanilla tweak mods (like 30 more science packs) to work well.

Thanks for the update.

Another error in case it doesn't pop with Ultracube (I'll have to try it sometime! After my current run and Nullius maybe...600 hours later):

Error while running event tier-generator::on_nth_tick(1)
tier-generator/control.lua:15: bad argument #0 of 1 to 'on_nth_tick' (Wrong number of arguments.)
stack traceback:
[C]: in function 'on_nth_tick'
tier-generator/control.lua:15: in function <tier-generator/control.lua:6>

Sorry for getting back to you so late.
I got very into the weeds making Ultracube work.
This new version has fixed the biggest bug that would be causing problems, as well as the fact that I forgot to pass nil to nth_tick
In my defense, it works just fine on linux, so I just assumed that's how it worked.

Ultracube still doesn't work out of the box, but if you dive into the files I've got the required settings in the file in the compatibility folder.
Proper compatibility will come soon, but I need to take a break after going slightly insane trying to track down a few bugs.
I really need a better way of debugging issues with this, all of mine are either a deluge of info or not enough :(

It works! My current setup has 35 tiers!

And, no apologies or rush is necessary! You folks do this work for no benefit but to yourself and the Factorio community - it is great what you do.