What balanced equation do you get when you add colorless sodium hydroxide to blue copper (II) nitrate to produce a light blue precipitate?

2NaOH + Cu(NO3)2 -> 2NaNO3 + Cu(OH)2

Although the previous equation is correct, you might prefer it in this form:
2Na+ +2OH- + Cu++ + 2(NO3)- -> 2Na+ + 2(NO3)- + Cu(OH)2
or
Cu++ + 2OH- -> Cu(OH)2
The Na+ and NO3- do not participate in the reaction.