Oops, it doesn't look like 'nikki bella day' is a national day..

Other days

fiancee

Fiancee Day
cursing

Cursing Day
nae nae

Nae Nae Day
pick me

Pick Me Day
girl friend

Girl Friend Day
bubble bath

Bubble Bath Day
boba

Boba Day
china

China Day
brow

Brow Day
pumpkin

Pumpkin Day