I'm getting an error loading mods screen when trying to open Factorio with just momo's tweak and its dependencies. The screen says:
Failed to load mods:MomosTweak/data-final-fixes.lua:20: attempt to index field '?' (a nil value) stack traceback:
MomosTweak/data-final-fixes.lua:20 in main chunk

Which Factorio version are you using? I just checked on 1.1.57 (current stable version) and seems working fine.
Can you try updating Factorio version and retry?

If that doesnt help then can you upload your save file somewhere and link it here so i can reproduce the problem?

Nvm. I deleted everything in my mods folder and reinstalled them and it works now. Everything was up to date but I guess some wires got crossed at some point.

After installing the latest Sea Block pack I received the above error. Disabling all new mods added by Sea Block pack did not fix the issue. I was able to by syncing a prior save.

Hi.
Its caused by changes in Angels mods and in SeaBlock mod.
I am working now on fix - will notify you when is done.

Ok - we got fix boys: https://mods.factorio.com/mod/MomosTweak/changelog , https://github.com/Archemide/MomosTweak/pull/4
:)

Please update your "MomosTweak" and "MoreSciencePacks-for1_1_0" mods and check if works.
It should work now with or without "SeaBlock Pack" mod.

If you will notice anything which is broken or doesnt work etc then dont hesitate to report here or in github.

Update: today new version of mod (1.1.6) was pushed with even more fixes (for uncraftable early game SeaBlock things) - see https://github.com/Archemide/MomosTweak/issues/6