Hi,
It appears as though it may be possible to replace just the plastic window as there is a replacement part available.
Here’s a link to a [https://www.ebay.com/itm/New-LCD-Window-Display-Acrylic-Outer-Glass-For-NIKON-COOLPIX-L330-L340-Camera/172070738101?hash=item28103718b5:g:tA8AAOSwM0ZbSccW:rk:10:pf:0|supplier] of the part. it is shown only to give you an idea of the cost of the part. There may be other suppliers online (I haven’t checked) that may suit you better. Just search for ''Nikon Coolpix L330 parts'' to get results
Here’s a link to the ifixit [guide|60447] guide. It doesn’t show how to remove the plastic window but it does show how to remove the back housing and hopefully once that is removed you’ll be able to ascertain how to remove/replace the window.
Hopefully this is of some help.