map.scss

//SCSS

$pages: ('home', 'about', 'products', 'contact'); 
$selector: ();

@each $item in $pages {
  $selector: append($selector, unquote('.#{$item} .nav-#{$item}'), 'comma');
}

#{$selector} {
  color: red;
}

//CSS

.home .nav-home, 
.about .nav-about, 
.products .nav-products, 
.contact .nav-contact {
  color: red;
}