It’s always hard to make the distinction between them.
From what i learnt : a nature spirit/land spirit is linked to a physical place of our realm.
A faery is a humanoid being or an animal that comes from another world (faeryland) but it’s somehow connected to our world.
Example : a nymph is a nature/land spirit cause it’s linked to a physical place/tree.
A faery woman is a spirit than can walk on the same land but doesn’t belong to it.
That being said, folklore and culture can mixed up those ideas.
Example : Clurichauns are seen as the spirits of the grains field and/or fey folks that are attracted to this places.