noun
how many nights
Used in questions or expressions of uncertainty about the number of nights.
ここに泊まるのは幾夜ですか。
How many nights will you stay here?
noun
some nights; several nights; a number of nights
Indicates an unspecified but relatively small number of nights. Often used in narrative or descriptive contexts.
幾夜も眠れない夜が続いた。
I had several sleepless nights in a row.