Answer
$CO_2$ - molecular compound
$NiCl_2$ - ionic compound
$NaI$ - ionic compound
$PCl_3$ - molecular compound
Work Step by Step
$CO_2$ - molecular compound, because it is composed of 2 non-metals
$NiCl_2$ - ionic compound, because it is composed of a metal and a non-metal
$NaI$ - ionic compound, because it is composed of a metal and a non-metal
$PCl_3$ - molecular compound, because it is composed of 2 non-metals
