A few days ago I run in an issue that by default NetBeans doesn't show files which starts with dot, which is exactly the case of .htaccess file. This is the tip how to do it.
Go to the Options->Miscellaneous->Files and the content of Ingnored Files Pattern field replace with:
If you have already .htaccess in the project and the file is not still displayed, then close the project and open again. There is issue #139582, which is entered against the project.