Chain oil aims to lubricate the cutting equipment (bar and chain) to ensure the chain moving free of friction against the bar to avoid overheating.
2-stroke oil is a special oil that is mixed together with the gasoline and serves as lubricant for the 2-stroke engine, as gasoline alone does not provide enough lubrication.
As the chain oil and 2-stroke oil has different purposes and properties, it is important to use the correct oil for the given purpose.