Don't worry about this other stuff, just check how much sodium and how much nitrate you need in the final solution, and calculate necessary amount of your given reagents needed for that. Note that neither Na+ nor NO3- will react, they will both remain unchanged in the solution.
And your reaction is wrong - there is no hydrogen between products and you missed NO3- on the right. Zn2+ + OH- may give zincate, so this part is more or less OK.