How to display dynamic navigation bar from blade template

I have a navigation bar stored in the database, and I have a Controller witch lists the navbar for my template file.

$navbar=/*Query*/
return view('inc.template')->with('nav',$navbar);

I have other pages where I want to use the template with the navigation bar of course, but when I extend the template I get error message 'Undefined variable $nav'. I understand why I get this error message, because I don't returned the variable for the other page. So I need solution for this.. every idea is welcome!.

I have single product page, where I want to include the template with the navigation bar and also I will list the Single Product here.

I know I can copy the query code and paste it to the single product controller, but I believe this is not a good solution (repeating myself).

Thanks in advance for your ideas!