Nesting views is a really common code smell and should be avoided. It's best to write each query as a stand-alone entity and not attempt code reuse through views or other objects. It seems counter-intuitive, but that's how SQL Server works best.

As for the number of reads from any given table, it just depends on how much data there is and how it's being accessed. There isn't a formula that says X is bad and Y is good. Instead you need to explore the execution plan.

Basically, you need to read the books in my signature line down below.