Answer
$Zn(NO_3)_2$
Work Step by Step
Zinc Nitrate is an ionic compound, so the charges between the Zinc ion and the Nitrate ion must cancel out. The Zinc ion has a charge of 2+, while the Nitrate ion ($NO_3-$) has a charge of 1-. In order to create a neutral ionic compound, there must be two Nitrate ions for every one Zinc ion. The metal (Zinc in this case) comes first in the chemical formula, so the chemical formula is $Zn(NO_3)_2$.