For the record, the term "nationalist" is not synonymous with "racist." In the present political climate, the term "nationalist" is easy shorthand for those who counter "globalist" ideology or agenda. Nationalist also seems applicable to those opposing "open borders."
I'll give Google credit, type "nationalist", and this is the definition that shows up: "a person who advocates political independence for a country." Seems a fair definition.
Because Trump policies are sometimes described as "nationalist," don't be surprised when those on the Left attempt to redefine the word with smearish overtones.
Yes, there have been groups in the past who used the term.
There have also been "progressives" who purged African Americans from federal employment.
Anyone have a problem with the government of Taiwan? It's also been known as Nationalist China when it sought differentiation from Communist China on the mainland.