Does Dell mouse MS111 work with macOS Sierra

Any USB power device like a mouse or keyboard should function on a macOS system. Their may be some limitations or features related to the macOS that may not be supported by the device though, but you basic primary/secondary clicking should work.

My right button selects and the left button pulls up the menu on OS Sierra. I would like to change it around.

The buttons work opposite. How do I change it?

You need to go to System Preferences and check under 'Mouse'. The menu is called a secondary click and a normal click is called primary.

Thanks. Your directions worked.