This criticism usually comes from people that do not use Nim. I was very surprised as well at first - now after 1 year of using Nim I realize I never run into any trouble because of case/underscore insensitivity.

#1: those variables have to be in the same scope or be procs working on the same types to be an issue.

#2: I don't use nimgrep, I just keep a consistent style across my files. When reading somebody else's code, case-insensitive search is usually enough.