Answer
The precipitate is copper (II) hydroxide
2KOH(aq) + Cu(NO$_{3}$)$_2$ (aq) -> 2KNO$_{3}$ (aq) + Cu(OH)$_2$ (s)
Work Step by Step
Ionic compounds containing hydroxide ions are insoluble unless they contain an alkali metal, barium, strontium, or calcium ion. Because hydroxide reacts with copper, it will form a solid precipitate.