Neck of the woods
The place where speakers live

Nerves of steel
A person who is not frightened by something easily

Nest egg
Money saved for emergency

New blood
New people / generation

New York minute
Something that happen very fast

Never do things by halves
Put much effort when doing something to finish it

Never never land
The ideal perfect place where people dream to go.

Night owl
A person who goes to bed very late

Nineteen to the dozen
Talk loud and annoying

No dice
No luck

No go
Something that is not going to work

New skin off my nose
Feel not impacted at all

No sweat   
Very close competition / No Problem

No quarter
Finish with no compromise

None the less / Nonetheless
However

None too
Not at all

Nose in the air
Act superiors than the rest

Not a Chance
Not at all

Not my cup of tea
Not my type / favorite

Not the end of the world
Not the worst. Use to comfort people

Nuts and bolt
The most important parts of something

Nuts
Crazy