You can nest IF functions as deep as you want,but after you get beyond a nest of three IF functions,the logic becomes difficult to follow.

Nest

To nest in computing refers to placing one or more elements, such as commands or functions, inside another element of the same type, creating a hierarchy.

IF Functions

A logical function in spreadsheets that returns one value if a condition is true and another value if the condition is false.

Logic

The study of reasoning and argumentation, or a systematic method of arriving at a conclusion based on a set of premises.