Its "Νίκη" and it comes from the name Nick which in greek is "Νίκος", so Nikki is the feminine...
That is sweet, where are u from? Aint u greek?
However, the full name would be "Νίκη Λιν Μονιόδη".
Although the dictation can be wrong, i mean at Μονιόδη the "o" could be "ω" as well, which is a vowel that is pronunced equaly to "o"...
Wish u the best
PS Νίκη in greek also means victory