What are the products of Potassium iodide + lead nitrate?
This is a double replacement reaction.
Potassium and lead are cations (positively charged ions).
Iodide and Nitrate are anions (negatively charged ions).
To find the products, you need to swap the anions with another cation and the cation with another anion.
So, you have Potassium Iodide and Lead Nitrate. You want to move the 'Nitrate' anion and place it together with the 'Potassium' cation then you also have to move 'Iodide' anion and place it together with the 'Lead' cation.
Potassium Iodide + Lead Nitrate => Potassium Nitrate + Lead Iodide