Thank you for your detailed bug report.
I built the nsis_3.09-1 and nsis-common_3.09-1 packages on Debian
Bookworm, installed the resulting packages and can confirm with the two
Nullsoft Installer (.nsi) scripts provided by you that the resulting
installer executables no longer show the "(.reloc) is too large" error
with objdump.
Therefore I would appreciate if you create a "bookworm proposed updates
request" by issuing the "reportbug release.debian.org" command on a
Debian system.
Please mention in "reportbug" this bug report, provide your observations
and results of your tests and also refer to the fixed security
vulnerability (Bug#1040880: nsis: CVE-2023-37378) in nsis_3.09-1.