The PR that is affecting you is nerdfonts: separate into individual font packages, 3.2.1 -> 3.3.0 by rc-zb · Pull Request #354543 · NixOS/nixpkgs · GitHub and as improvement for the error message nerd-fonts: improve alias throw to give example migration by anund · Pull Request #362769 · NixOS/nixpkgs · GitHub
According the migration content in the pr you want to switch to
home.packages = with pkgs; [
nerd-fonts.jetbrains-mono
];
Which should be equivalent to your old declaration as far as i can see.
edit: nvm, saw that you tried that out
edit2:
You might want to double check your kitty config if that is refering the path somewhere.
What i actually see is that there is a change in the path from share/fonts/truetype/NerdFonts/JetBrainsMonoNerdFont-SemiBold.ttf to share/fonts/truetype/NerdFonts/JetBrainsMono/JetBrainsMonoNerdFont-SemiBold.ttf , so either the config or some font cache might refer to the old/wrong font location