Point 217 in the category of MODALITY is defined:
invert ‘must’ and the subject after negative phrases, e.g. ‘not only’, ‘never’, ‘nor’, to change the focus and give prominence/emphasis.
*Note ‘nor‘ is already covered in other C2 grammar points.
This is extremely rare grammar! iWeb doesn’t find or allow much detail for these searches. The best we could do is:
nor must * _V
1 NOR MUST IT BE 71
2 NOR MUST WE FORGET 45
3 NOR MUST THEY BE 17
4 NOR MUST WE OMIT 14
5 NOR MUST I FORGET 12
6 NOR MUST WE OVERLOOK 11
EXAMPLES:
Not only must we be prepared for it, but we must also be ready for the challenges to our rationality that come with it.
Forexlive – Coping with Bitcoin volatility
Never must we forget the hundreds who floated down the Ganga.
Free Press Journal
Nor must he necessarily wait until the 2024 election.
RealClearPolitics – Donald Trump: The Once and Future President?