Does nieces need a apostrophe

If you wanted to say "nieces" as a plural, such as "I have two nieces", then it wouldn't need an apostrophe. If you wanted to say something like "My niece's teddybear", showing singular possession, then you would need an apostrophe.

The Word nieces is a plural noun. If you want to use it as a plural possessive noun then put an apostrophe at the end - nieces'

My nieces' husbands are both doctors.