"Nikki" is typically a nickname for the given name "Nicole" in English. It does not have a direct translation in Spanish as it is a name.
Nicaragua is already IN Spanish. It is pronounced a bit differently in Spanish than in English, it is pronounced, "nee-cah-RAH-gua." Sites such as learn-spanish.co.il provide audio pronunciations of many common Spanish words.
Nikki Blonsky goes by Nikki, and Nikki "B".
Nikki Charm goes by Nasty Nikki, and Naughty Nikki.
Nikki Ali is 5' 7".
Nikki Falk is 5' 6".
well... scene girls(and boys) usually make up just random names. if you want to make a name out of nikkii you can do... nikki rainbow nikki hearts nikki murder nikki smiles nikki ectasy nikki gorgeus nikki monster
Nikki Timmons goes by Nikki.
Nikki Noyce goes by Nikki.
Nikki Marrone goes by Nikki.
Nikki Nova goes by J. Nichole Italiano, and J. Nichole Italiano-Zaza.
Nikki Grahame goes by Princess Nikki.