Serve remote files instead of local ones (with a nitro setup)
There's a couple different ways to handle this.
Base URL on Asset Volume
One way is just to treat the asset volume like you might a CDN.
Unlike other CMS (ahem WP), Craft doesn't hardcode URLs into the database and will build them up on-the-fly.
On the local dev server, you just need to set the base url (i.e. server name) of a volume to that of the production server instead of serving locally.
Your Asset volume config might look something like:

Instead of setting a value in the control panel, you can also use an alias if you want to advantage of Craft's multi-environment support.
Server Rewrites
If you have other assets that aren't necessarily managed by Craft, you can do some server rewrites like you did using Apache's .htaccess config.
Nitro uses nginx as the web server, not Apache, so there's not quite a direct equivalent of .htaccess other than editing the configuration (which is easy enough to do).
You'd want to ssh in to the appropriate container and then edit the nginx config (usually located in /etc/nginx/sites-enabled/yourtestservername.
To make the server rewrite work, try something like:
location ^~ /images {
return https://productionserver.example.com$request_uri;
 }
 

Place this before the closing bracket &quot;}&quot;. This assumes your asset volume is stored at &quot;/images&quot;. If you have any others, you can add them separately. nginx will redirect any content that's in /images to the production server.