how do I find the products of a chemical equation?
e.g.. NiCl2+NaOH --->?

I think (that means I may be wrong) that a precopitate will be formed.

For example, any iron(II) salt, mixed with sodium hydroxide will form a green precipitate.

Similarly, nickel, being a transition metal will form insoluble nickel hydroxide, which is perhaps green in colour.

The sodium will perhaps become a chloride salt.

Where does nitric acid come from? This was not in the original question and it's answers like that that might give you negative reputation.