Do Other Nationalities Other Than Scots Wear Scottish Tartans And If So Which Ones?

The tartan has been adopted by other nations for a variety of reasons.

Austria has the Austrian tartan.
The Canadians have the Canadian Centennial Tartan'; this is used as a 'national' tartan for all Canadians regardless of ancestry .
France
The French were supporters of  the Stuart / Jacobite cause and adopted the "Jacobite" tartan.  French soldiers  fought at the Battle of Culloden during the Jacobite rebellion of 1845.
Germany home of Prince Albert, have the Coburg tartan..   The "Coburg" tartan was created to commemorate the Prince Consort who, himself, designed tartans.

The Dutch have a tartan which represents both the House of Orange and the MacKay family who have been prominent in both Scotland and the Netherlands for many years.

In theory the tartan is wore by those with particular clan associations through clan, family, marriage etc., but many people of no- Scottish ancestry wear the tartan because they enjoy doing so.