In my opinion, the white precipitate is the product, you can analyse it through TLC or MS.
Second, NH4Cl is Louis acid, it can react with NaBH4, which has basicity.
And third, LiAlH4 has stonger reductive than NaBH4, and it's much more expensiver. So I don't think it's a good idea to substitute NaBH4 with LiAlH4, while NaBH4 could make the reaction .