There's a merged pull request on the void-packages repository

nix: increase open files limit.
https://github.com/void-linux/void-packages/pull/42311

Description:
The new value is the same as the one of NixOS:
<https://github.com/NixOS/nix/blob/601849b95afc3d173ea34ff5dba6353f9b71b495/misc/systemd/nix-daemon.service.in#L12>

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